tag:blogger.com,1999:blog-17261769186324109222024-03-05T19:59:01.199+08:00Living with PhysicsThis is blog dedicated to all the students taking physics, the teachers teaching Physics and anyone who wants to find out more about Physics. There will be articles on commonly asked questions by students, examination tips, teaching resources that the teacher uses and any interesting articles and events related to Physics or the teaching of it in this blog.Anonymoushttp://www.blogger.com/profile/01720801784103008765noreply@blogger.comBlogger49125tag:blogger.com,1999:blog-1726176918632410922.post-25357989409100421562015-07-31T16:09:00.000+08:002015-07-31T16:09:35.557+08:00Extension Activity for Oscillations - Moment of Inertia of a Tennis Racquet I am back teaching the SMTP (Science and Math Talent Programme)students again and yes, it is truly a pleasure teaching them. Is it challenging and stressful? Yes, it is :). Just as I push them, they push me as well and it is great pleasure to be learning.
<br />
<br />
I just did a great activity with them. We have been studying oscillations (A-level syllabus) and I had been wanting to do greater extensions with them. So we decided to move into Oscillations of a Physical Pendulum. Using a journal reading from Physics teacher as a base. I got the students to break up the journal into unfamiliar concepts and pen down questions that they would like to ask. We rearranged the questions and concepts into chunks and logical flow and then I assigned each group to look into the questions. They are to present the concepts within 5-10 min at next tutorial (3 days later).
<br />
<br />
<br />
<b>Details Activity:</b><br />
<strong></strong><br />
<strong>Objectives : </strong><br />
<ul>
<li>To understand the mechanics of a Physical Pendulum and see its relevance in a real life context</li>
</ul>
<strong>Article :</strong><br />
<ul>
<li><a href="http://scitation.aip.org/content/aapt/journal/tpt/23/4/10.1119/1.2341781" target="_blank">The</a> moment of inertia of a tennis racket - by Howard Brody</li>
<li><a href="http://scitation.aip.org/content/aapt/journal/tpt/23/4/10.1119/1.2341781">http://scitation.aip.org/content/aapt/journal/tpt/23/4/10.1119/1.2341781</a></li>
</ul>
<strong>Lesson Outline:</strong><br />
<ul>
<li>5 min : Self-Reading of article and pen down questions that you like to ask.</li>
<li>5 min : Within team consolidate and list down the questions that you think you need to ask and need to know the answers to to allow you to understand the article.</li>
<li>10 min : Teacher discuss and pen and arrange concepts and questions on the board, chunk them them into pieces to assign (with discussion with students). Each team picks the question they would like to work on to prepare a 5 -10 min presentation.</li>
</ul>
<strong>Questions raised by students :</strong><br />
<ul>
<li>Team 1 : What is Moment of Inertia? What is its Significance? How do we determine it for different shape objects.</li>
<li>Team 2: How is moment of inertia related to rotational motion?</li>
<li>Team 3 : What is parallel axis theorem? When is it used?</li>
<li>Team 4 : What is a physical pendulum and how does it work?</li>
<li>Team 5 : Understanding the Article : Aim, Significance, Method</li>
<li>Team 6: Understanding the Article : Results, Analysis and Interpretations and Conclusions.</li>
</ul>
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<ul>
</ul>
Anonymoushttp://www.blogger.com/profile/01720801784103008765noreply@blogger.com0tag:blogger.com,1999:blog-1726176918632410922.post-34801814610229841682015-01-07T09:18:00.002+08:002015-01-07T09:18:06.544+08:00Teaching Resources - Nuclear Physics<h2>
<span style="color: #20124d;">Videos</span></h2>
<h3>
1. The Most Radioactive Places on Earth</h3>
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<strong class="watch-time-text">Published on Dec 17, 2014 by Veritasium</strong></div>
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Who on Earth is exposed to the most ionizing radiation?<br />
[Check out Audible: <a class="yt-uix-redirect-link" dir="ltr" href="http://bit.ly/AudibleVe" rel="nofollow" target="_blank" title="http://bit.ly/AudibleVe">http://bit.ly/AudibleVe</a>]<br />
A documentary for TV about how Uranium and radioactivity have shaped the modern world to be ll be broadcast in mid-2015, details to come. The film goes to the most radioactive places on Earth (and some places, which surprisingly aren't as radioactive as you'd think). Chernobyl and Fukushima were incredible to see as they present post-apocalyptic landscapes. It also visits nuclear power plants, research reactors, Marie Curie's institute, Einstein's apartment, nuclear medicine areas of hospitals, uranium mines, nuclear bomb sites, and interviewed numerous experts.<br />
<br />
Notes about measuring radiation:<br />
Sieverts are a measure of 'effective dose' - that means they measure the biological impact of the energy transferred to tissues from radiation.</div>
Anonymoushttp://www.blogger.com/profile/01720801784103008765noreply@blogger.com0tag:blogger.com,1999:blog-1726176918632410922.post-19342201804261458152015-01-03T17:46:00.001+08:002015-02-02T09:50:11.726+08:00Advanced Level H2 Physics Chapter 1 Measurements - Framework of Concepts (In Progress)Before I plan my lessons and assessment and what I want to teach for Physics, I tend to write down a framework of concepts for my lessons. I looks similar to the syllabus but more in detail as I tend to break it down further into skills and specific concepts that I want to teach. Decided to document them here and add on it and hope it will be useful to all.<br />
<br />
If you think that I have missed out anything points and wish to add on, do leave your comments and I will look into it.<br />
<br />
<h2>
<span style="color: #073763;">Topic 1 Measurements</span></h2>
The topic of measurements consists of 4 main subtopics:<br />
<br />
1.1 Physical Quantities and Units<br />
1.2 Errors and Uncertainties<br />
1.3 Scalars and Vectors<br />
1.4 Orders of Magnitude<br />
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<h3>
1.1 Framework of Concepts and Skills for Physical Quantities and Units</h3>
<iframe height="3100" src="https://docs.google.com/document/d/15Oz-f6nmcSN-wA0d6J15nLMgBMsaOZY9VmFrJHucCgQ/pub?embedded=true" width="700"></iframe><br />
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<h3>
<span style="color: #0b5394;">1.2 Errors and Uncertainties- 2 Feb 2015</span></h3>
<div>
For Physics at A-levels, the treatment of errors and uncertainties is simplistic and yet difficult for students. We do not do standard deviations and variance in Physics but get students to understand that quantities that are measured have some inherent uncertainty in them and these errors propagate to the calculations and hence there are inherent errors even in derived values.</div>
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<br /></div>
<div>
The rules to get the uncertainties are rather straightforward, however as they are not derived for students, students do not understand that these are therefore just estimates. For my classes I tend to do the derivations with them and then also look into other methods for determining the uncertainties e.g. calculus and statistics to broaden their horizon. </div>
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<br /></div>
<div>
They is the first part where students themselves realize that there are no standard answers, like in secondary school, for Physics. Many stump at the qualitative parts as tutors (and examiners) give contextual questions where often experiments and results are shown and students are expected to identify systematic and random errors. Most give very generic answers not pertaining to the question or fail to explain why the error they have identified is a systematic or random one and hence often do not gain credit. Assessment of the contextual question can be done either in main paper or practical paper.</div>
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<iframe height="1000" src="https://docs.google.com/document/d/1vW2DQUSTUAE0hkBxoxAktYZtTz9cI24SOPElNyUugsU/pub?embedded=true" width="700"></iframe>
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<span style="color: #0b5394;">1.3 Vectors and Scalars - 2 Feb 2015</span></h3>
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<br />Anonymoushttp://www.blogger.com/profile/01720801784103008765noreply@blogger.com0tag:blogger.com,1999:blog-1726176918632410922.post-21056300313041794812014-06-01T16:28:00.001+08:002014-12-20T12:10:14.682+08:00Possible Ideas of Physics Investigative Project (1st Edit on 1 June 2014)I love food and cooking and I love Physics. I have always wanted to marry the two of them together. Recently, I have been doing this very wonderful course online in Edx on Food Sciences, and this has brought some inspiration for me to perhaps do this as part of my Physics Investigative Project for my next batch of year 1 students in GATE.<br />
<br />
At the school at I teach, we encourage teachers to go beyond the daily formative pen and paper assessments or the termly summative assessments. To encourage all departments and students to do alternative forms of assessments, each subject will need to have some alternative forms of assessments for students.<br />
<br />
For Physics, the tutors all agree that there should be more focus on investigative work that is done by the students and in the meanwhile they can be taught (hm....perhaps not taught....because we don't explicitly teach) scientific reasoning. We also want the students to get down to planning and doing experiments that are not so "cookbook" style as real investigations are never like that. Projects are also done in groups to allow students opportunities to work in teams to hone their teamwork skill....hm....though they often hate this part.<br />
<br />
Anyway.....back to the story, although we have similar goals in mind, we can never completely agree on what projects are to be done and how they are to carried out. But for my GATE class because there is only one class and I often take them on their own, I can essentially carry out the projects with great flexibility.<br />
<br />
Okay....going further back up, let me not lose track, cause I can be a little long winded at times.....what is this post for? I have some ideas that I hope to implement for PIP as I am going through my Edx course with Harvard. So I decided to record them here and so I won't forget. For those of you who are interested, feel free to pick up on these ideas or if you think you have something even better, please leave comments.<br />
<br />
<b>Project 1 : Cooking the Perfect Egg</b><br />
<b>1. Literature Review : </b>The Science of Cooking an Egg.<br />
2. Students to investigate the specific heat capacity of an egg.<br />
<b>3. </b>At the end of the project, they will be given hot water and 4 eggs and they will have cook a perfect soft boil egg (Singapore Breakfast style)<br />
<b>4.</b>They need to explain using sound scientific principles how they are able to attain it. They have to come up with a general scientific equation on their method such that the equation can allow for cooking of a varying no. of eggs up to 10 eggs and test you their scientific equation).<br />
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<b><br /></b>Anonymoushttp://www.blogger.com/profile/01720801784103008765noreply@blogger.com0tag:blogger.com,1999:blog-1726176918632410922.post-85253478796202140662014-05-05T13:48:00.001+08:002014-05-05T13:51:29.583+08:00Misconceptions In Photoelectric Effect<h2>
<b><span style="color: #0b5394;">Photoelectric Effect Misconceptions and Questions Asked By Students</span></b></h2>
<br />
<br />
Both my classes started on the photoelectric effect tutorial last Friday. As the students were presenting their summaries to the rest of the class for one of my classes, one of the girls suddenly turned and asked me, "Why do the photoelectrons emit with different kinetic energy?". Today, I went into my GATE class and during group discussions, I not only picked up this question from a student to another friend and other question related to the same idea. Hm....to help me and other teachers who may be teaching the topic, I decided to document them down here. <br />
<br />
<b><span style="color: red;"> Questions/Comments made by students:</span></b><br />
<br />
1. "Why do photoelectrons ejected from the metal with different kinetic energies?"<br />
<br />
2. "So does each electron in the metal have their own workfunction?"<br />
<br />
3. " The electrons are each in a different shell and hence they will require a different energy of emission".<br />
<br />
4. "But we just did line spectra in lecture, so are you saying that the electrons are excited? And hence at different energies? But if all the electrons are at ground state then would they be at the same energy level?"<br />
<br />
5. "So workfunction and ionisation energy is the same? Because they are the minimum amount of energy to liberate an electron? "<br />
<br />
I guess what I will do is that I shall flash all these comments on the board for discussion on Wednesday and I guess that should generate some interesting discussions for the class. :) <br />
<br />Anonymoushttp://www.blogger.com/profile/01720801784103008765noreply@blogger.com0tag:blogger.com,1999:blog-1726176918632410922.post-56935216599092205262014-02-27T09:25:00.001+08:002014-02-27T09:25:30.271+08:00Sharing My Classes This year, one of my class was split up as some of the students were struggling with Physics and we felt that having a dedicated teacher to guide a smaller group would give them the learning structure and allow for greater differentiated learning within the class and hopefully build more self-confidence in them.<br />
<br />
Am I enjoying it? Definitely! Actually, I am feeling the benefits of it myself and it is extra benefits that I would not have reaped. I did have split classes before, but this time it is a different. Maybe it has to do with the fact that both us have busy schedules and ended up half the time, we still took each other half classes and relieved each other.<br />
<br />
What ended up was that we had to keep communicating to each other what each of doing. We then went in to prepare the labs together, talked more about how to teach the class and what each wanted to do :) Haha....we had more synergy!<br />
<br />
This was really a pleasant surprise.Anonymoushttp://www.blogger.com/profile/01720801784103008765noreply@blogger.com0tag:blogger.com,1999:blog-1726176918632410922.post-23621481219358423172013-04-04T11:14:00.001+08:002013-04-04T11:14:41.479+08:0002 Kinematics<h2>
02 Kinematics</h2>
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<h3>
Laboratory Work</h3>
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Video Tracking Software</h3>
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<li><h4>
<u><span style="color: #351c75;">Tracker : A Video Analysis Software (Free!)</span></u></h4>
<h4>
<u><span style="color: #351c75;"></span></u></h4>
Site: <a href="http://www.cabrillo.edu/~dbrown/tracker/">http://www.cabrillo.edu/~dbrown/tracker/</a><br />
<br />
Tracker is a free video analysis and modeling tool built on the <span style="color: black;"><a href="http://www.opensourcephysics.org/" target="_blank">Open Source Physics</a> (OSP) Java framework. It is designed to be used in physics education.</span><br />
<br />
<span style="color: #351c75;"><span style="color: black;">This site contains the installation software as well as some videos and necessary software. </span></span><br />
<h4>
<br /></h4>
</li>
</ul>
Anonymoushttp://www.blogger.com/profile/01720801784103008765noreply@blogger.com0tag:blogger.com,1999:blog-1726176918632410922.post-25994654367731249852013-04-03T22:42:00.008+08:002013-04-03T22:42:55.051+08:0002 Kinematics<h2>
02 Kinematics</h2>
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<br />
<h3>
Laboratory Work</h3>
<h3>
Video Tracking Software</h3>
<ul>
<li><h4>
<u><span style="color: #351c75;">Tracker : A Video Analysis Software (Free!)</span></u></h4>
<h4>
<u><span style="color: #351c75;"></span></u></h4>
Site: <a href="http://www.cabrillo.edu/~dbrown/tracker/">http://www.cabrillo.edu/~dbrown/tracker/</a><br />
<br />
Tracker is a free video analysis and modeling tool built on the <span style="color: black;"><a href="http://www.opensourcephysics.org/" target="_blank">Open Source Physics</a> (OSP) Java framework. It is designed to be used in physics education.</span><br />
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<span style="color: #351c75;"><span style="color: black;">This site contains the installation software as well as some videos and necessary software. </span></span><br />
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Anonymoushttp://www.blogger.com/profile/01720801784103008765noreply@blogger.com0tag:blogger.com,1999:blog-1726176918632410922.post-65805374539234592013-04-03T18:16:00.000+08:002015-01-12T16:06:07.564+08:0001 Units and Measurements: Teaching ResourcesIntroduction:<br />
I realised there are many resources on the web and because I don't systematically keep them, I often spend loads to time searching for something that I came across before. So I decided to start keeping track of them (hm....and hopefully) update them regularly, so I don't have to spend loads of time searching for them.<br />
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<h2>
<b>Topic 1 Measurements</b></h2>
<h3>
<b> </b><b>1.1 Physical Quantities and units</b></h3>
<h4>
<b>Possible Lesson Flow</b></h4>
<div>
12 Jan 2015</div>
<div>
<br /></div>
<div>
Today I observed a great lecture by my colleague, Arthur. Really liked the way he progressed through the lesson. So I decided to document it here, briefly.</div>
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<br /></div>
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<u>Lecture Outline</u></div>
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<br /></div>
<div>
1. What is Science and Physics ?</div>
<div>
<ul>
<li>systematic enterprise (scientific method)</li>
<li>testable explanations + predictions -> experimentation.</li>
</ul>
<div>
2. What is Scientific method:</div>
</div>
<div>
<ul>
<li>Based on observations forming testable hypothesis -> predictions which is testable by experimentation.</li>
<li>After many cycles of experimentation if the hypothesis works then we form theories.</li>
<li>Arthur used a very interesting example of apple falling from tree and an invisible string that holds the apple to the Earth.</li>
</ul>
<div>
3. What do we do in experimentation?</div>
</div>
<div>
<ul>
<li>Measure (apparatus) / Calculate and collect and analyse scientific data and reach conclusions</li>
</ul>
<div>
4. Physical Quantities and Units</div>
</div>
<div>
<ul>
<li>Many of the data that we collect in physics are quantifiable.</li>
<li>Brings us to what is a physical quantity. </li>
<li>What can we do with physical quantity :</li>
<li>Law of Homogeneity of equations can be introduced here.</li>
<li>Comet and probe exercise on what physical quantities are we interested in.</li>
</ul>
</div>
<div>
<br /></div>
<br />
<h4>
<b> </b><b>Video Resources:</b></h4>
<b style="color: #073763;"><br /></b>
<b style="color: #073763;"> </b><u style="color: #073763;"><b>Video 1 : Redefining the mass (1 kg) - the roundest object on earth.</b></u><br />
<ul>
<li><b> </b>A beautiful video to be used on teaching the base quantities and units.</li>
<li>Discusses about how calibration standards change.</li>
<li>And how amongst the 7 fundamental quantities, only mass is still defined in terms of a carefully kept prototype in France and the problems with it.</li>
</ul>
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<br />Anonymoushttp://www.blogger.com/profile/01720801784103008765noreply@blogger.com0tag:blogger.com,1999:blog-1726176918632410922.post-80958001730976145012012-07-12T14:40:00.001+08:002012-07-13T11:00:40.288+08:00World Conference on Physics Education 2012- Physics as a Culture12th July 2012<br />
<br />
Ok....I am back in Singapore. Have been back a week actually.....but was having jetlag and had piles of work to clear and I could not update this blog. But I think it is essential, else as time passes, my memory will most likely undergo an exponential decay. And I find that my half life of my short term memory has been getting shorter over the years as well. Ok, so I will try and find 30 min to blog about some of the interesting insights or information that I got from the the conference.<br />
<br />
Actually this is good, cause I will therefore only blog about the things that impacted me the most.<br />
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<div style="color: purple;">
<b><span style="font-size: large;">Crossing the Culture in Physics Education</span></b></div>
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<span style="font-size: large;">This is the key theme of this year's conference about the role of context and culture in teaching physics.</span></div>
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<tr><td style="text-align: center;"><span style="font-size: large;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiLoMr_US3prn4Z7ew3zBx4BhnzhzYjamMevpgFxCuiWkiNwcTzYMng8nroDF9-4M2MdvCc86jZcB1d53aOichgtB1CBwo-cQld4NfXZxlnOE5n4oE6CPiNTCkRccrtAHj6BkzFbmhIpqc/s1600/IMG_1129.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiLoMr_US3prn4Z7ew3zBx4BhnzhzYjamMevpgFxCuiWkiNwcTzYMng8nroDF9-4M2MdvCc86jZcB1d53aOichgtB1CBwo-cQld4NfXZxlnOE5n4oE6CPiNTCkRccrtAHj6BkzFbmhIpqc/s320/IMG_1129.JPG" width="239" /></a></span></td></tr>
<tr style="font-family: "Trebuchet MS",sans-serif;"><td class="tr-caption" style="text-align: center;"><h3>
<span style="font-size: x-small;">Prof Edward F. Redish giving his plenary talk to start off the conference.</span></h3>
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<div style="font-family: "Trebuchet MS",sans-serif;">
<span style="font-size: large;"><span style="font-family: inherit;">One glance at the theme, one would actually think that "cross culture" is between the Asians, Hispanics, and Caucasians etc. Actually, I was surprised that there was another way to think about this cross-culture thingy....i.e. to think about it in terms of disciplines.</span></span></div>
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<span style="font-size: large;"><br /></span></div>
<div style="font-family: inherit;">
<span style="font-size: large;">Hm, and come to think of it, it is quite true for me as a student. Let me try to elaborate and summarise the gist of what I find interesting from Professor Redish's talk...and hopefully I don't get it wrong.</span></div>
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<span style="font-size: large;"><br /></span></div>
<div style="font-family: inherit;">
<span style="font-size: large;">1. <b>Physicists, chemist, biologists and those who study math or literature when given a same problem could think of it differently and also interpret the ideas different. Hence, they approach a question and solve it in their own unique manners. </b></span></div>
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<span style="font-size: large;"><b>2. What is therefore important for Physicists and which we seem to think are fundamental - like forces and energy. May not be so fundamental for students who take biology and medicine,as they belong to another culture. </b></span></div>
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<span style="font-size: large;"><br /></span></div>
<div style="font-family: inherit;">
<span style="font-size: large;">Prof. Redish talked about teaching undergraduates not taking Physics as a major, hm...my mind was running through images of my students who are offering literature, history and who has not inkling why they chose to do physics at A-levels in the first place. Ok....I still think forces and energy is fundamental, I cannot image why not. I cannot see the value of literature except for enjoyment...(don't throw rotten eggs at me....I do read classics and literature....for fun....but have a fundamental respect for Physics), but I guess my lit. students could possible see no value in Physics for themselves. I guess this helps me to understand them better and develop an empathy for them and not be so impatient with them.<b> </b></span></div>
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<span style="font-size: large;"><b><br /></b></span></div>
<div style="font-family: inherit;">
<span style="font-size: large;"><b>3. It takes time for students to inculcate the habits for them to think like physicists. It is not natural to them. We must articulate our thoughts and constantly show them how we look at things.</b></span></div>
<div style="font-family: inherit;">
<span style="font-size: large;"><b><br /></b></span></div>
<div style="font-family: inherit;">
<span style="font-size: large;"><b>3. Physics is a culture, students are at the edge of this culture, observing and learning more about the culture. We need to help them to slowly cross over the culture - hm it means starting from primary school I guess - and understand the culture before we can move them in.</b></span></div>
<div style="font-family: inherit;">
<span style="font-size: large;"><br /></span></div>
<div style="font-family: inherit;">
<span style="font-size: large;"><b>4. Many a times, we do not really understand Physics. We think we understand Physics. In reality, it is just that we are exposed to the same concepts many times at different angles and we start accepting the concepts and think we know them.</b></span></div>
<div style="font-family: inherit;">
<span style="font-size: large;"><br /></span></div>
<div style="font-family: inherit;">
<span style="font-size: large;">When I look at my son doing electricity at Primary school, I can better understand the problems he is getting now? Electricity and many concepts in physics are actually quite abstract to the students, cause these can be seen. We cannot see forces, we cannot see energy and we cannot see electrons. We develop these as we go along and with sufficient exposure and experiments, we believe in them.</span></div>
<div style="font-family: inherit;">
<span style="font-size: large;"><b> </b></span></div>
<div style="font-family: inherit;">
<span style="font-size: large;">No wonder my son is having problem with forces and energy and treating them as equivalent and I am pulling my hair out trying to teach him. </span></div>
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<span style="font-size: large;"><br /></span></div>
<div style="font-family: inherit;">
<span style="font-size: large;">No wonder some students till now still mixes up concepts of forces and motion, as they "see" only the effect.</span></div>
<div style="font-family: inherit;">
<span style="font-size: large;"><br /></span></div>
<div style="font-family: inherit;">
<span style="font-size: large;">Hence, I guess we need to also to be tolerant of our students and give them time to explore the concepts till they are able to accept it.</span></div>
<div style="font-family: inherit;">
<span style="font-size: large;"><br /></span></div>
<div style="font-family: inherit;">
<span style="font-size: large;">....................................................................................................</span></div>
<div style="font-family: inherit;">
<span style="font-size: large;"><b><br /></b></span></div>
<div style="font-family: inherit;">
<span style="font-size: large;"><b>Further revelation:</b></span></div>
<div style="font-family: inherit;">
<span style="font-size: large;"><b><br /></b></span></div>
<div style="font-family: inherit;">
<span style="font-size: large;">Hence, for those of us who have immersed in physics long enough, when we see equations, we may be able to have mental physical models of what that equations are. For students, they are at the stage of infancy when to them the equations are algebraic equations with no form or shape or significance. They do not see mental models, they are often unaware of assumptions behind the equations. This does not help if the tutorial practices in schools and the assessment questions are choked with plug-and -chug question cause they will only see that searching for the correct no. associated with the symbols and chugging into the magic equations will yield the answer and think that they "understand" their physics. </span></div>
<div style="font-family: inherit;">
<span style="font-size: large;"><br /></span></div>
<div style="font-family: inherit;">
<span style="font-size: large;">Again, we therefore need to get students to interpret their calculations, have more conceptual and explanation questions if we want to develop their thinking in physics.</span></div>
<div style="font-family: inherit;">
<span style="font-size: large;"><br /></span></div>
<div style="font-family: inherit;">
<span style="font-size: large;">Ok....I am not saying there is no place in physics for drill questions. If I look at my own learning and do a self-reflection. I find that I always start with the plug and chug questions, cause I am gaining familiarity with the concept, then I look at the different ways they are applied and see how they work. When I have build sufficient confidence, and can use the equations without having trouble even to remember its basic form, I then move on to look at it more conceptually and then applying them to more complex situations. </span></div>
<div style="font-family: inherit;">
<span style="font-size: large;"><br /></span></div>
<div style="font-family: inherit;">
<span style="font-size: large;">Now looking back on our lecture tutorial systems, I feel that more should be done in the area of bridging between the lecture and tutorials. The lectures often introduces the concepts, and and examples often are looking a plug and chug question. Then we move on to some self-review question and discussion questions. But our self-review questions are often not planned through with a clear learning path and purpose in mind. The bridge between the self-review questions are often not clear as well. In fact, sometimes the jump is very, very big. We should try the lay stepping stones and step them from basic and build concepts on each other, before assimilating them with concepts from other areas. I know that is going to be massive work. And with us trying to limit the tutorials to about 10+ questions. It will definitely be a challenge.</span></div>
<div style="font-family: inherit;">
<span style="font-size: large;"><br /></span></div>
<div style="font-family: inherit;">
<span style="font-size: large;"><b>Footnote</b>:</span></div>
<div style="font-family: inherit;">
<span style="font-size: large;"><br /></span></div>
<div style="font-family: inherit;">
<span style="font-size: large;">You must be thinking...why do I only update the blog now. Network in Turkey is slow....very slow, and it does not help when the hotel you stay at has network that is intermittent and unreliable.</span></div>
<span style="font-size: large;"><br /></span><br />
<br />Anonymoushttp://www.blogger.com/profile/01720801784103008765noreply@blogger.com0tag:blogger.com,1999:blog-1726176918632410922.post-86718807759688584112012-07-12T13:57:00.002+08:002012-07-13T11:01:35.153+08:00World Conference on Physics Education 2012 - 30 June 2012We flew to to Istanbul on Emirates transiting at Dubai. We were not told on the website when we booked the tickets that there was a stop at Colombo where we made a stop for an hour to drop off some passengers and pickup others. In all the flight was okay, except that the seats were a little tight and I had this lady with his boy who kept putting things over to my seat and then putting the legs over to me as well.<br />
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<tr><td class="tr-caption" style="text-align: center;">Transiting at Dubai Airport</td></tr>
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The transit at Dubai airport was a wait for approximately 4 hours. Chiu Wai and I walked around to get a table to do some work, but there were only lounge chairs all around. Cafes and restaurants were mainly quite packed and finally we had coffee (of course Chiu Wai will not have coffee, he had hot chocolate) at a cafe. We chatted on work as we could not get any internet connections up though and had lunch later at Burger King. We managed to locate the information counter to ask about wireless connection, but alas we were hungry by then and decided to eat instead.<br />
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Finally arrived at Istanbul Airport Atartuk at around 3 pm Istanbul time. We waited for more than 30 minutes before we could collect luggage. Managed to change some of my pounds leftover from the UK trip I went in 2009 to Turkish lira...though they gave me all in 100 notes. Decided against changing all as the money changers in the airport will charge a commission of 4% and also it was difficult to change TL back to SGD in Singapore, so didn't want to incur additional charges again.<br />
<br />
I bought a Turkcell SIM card so that I had data plan in Turkey, but it did cost me 85TL with only 30 TL value. <br />
Later note: By the time you activate it, Turkcell would have sent you a few SMS and you have only about 28TL left. I could not activate the other prepaid broadband plans using the instructions from http://prepaid-wireless-internet-access.wetpaint.com/page/Turkey+Turkcell, and could not check my balance, in the end. I just only surfed on 3G when necessary, keeping my fingers crossed that my money was available.<br />
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Figuring the way to the hotel was a nightmare, a few Taxi drivers could not know where our hotel was, it added to the frustration that our hotel was changed 2 days before the trip and after we have paid like 1 month ago! A brave taxi driver finally claimed he knew were it was, though he was later all on the phone asking people where the hotel was. And closer to the place, he had to ask a few more people walking on the road where it was. Arggh! So obviously, it was not so obvious! But finally we found one kind soul who knew it was. It was in a quieter part near Taksim square down a very steep slope which is a chore to climb everyday.<br />
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<br />Anonymoushttp://www.blogger.com/profile/01720801784103008765noreply@blogger.com0tag:blogger.com,1999:blog-1726176918632410922.post-14702028333687340142012-06-29T09:36:00.002+08:002012-07-12T13:56:10.955+08:00My Trip to World Conference on Physics Education 2012@ Istanbul I am rushing now to prepare for the World Conference on Physics Education 2012 at Istanbul, arghh...have yet to pack and am rushing to pack now. Having butterflies in my stomach and I have yet to go.<br />
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I will be presenting a paper for the conference on EM Preconceptions for Physics Students in my school. Was originally scheduled to present on the 3rd July, but now has been postponed to the 5th July (Thursday). Guess what? I am still rushing my school other work datelines - but okay, after I put this down, I will then go back and look at the data....and do up the slides. <br />
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But the program looks exciting, the program has so many concurrent sessions and the abstracts are so thick - over 400 pages. I won't print them then.....will go the the venue to collect. But I am so excited and I hope to learn something more there.<br />
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Anyway conference programmes are here, do take a look at them by following the link below. Hm...there was suppose to be a teacher's programme to visit schools in Istanbul, I am interested in it as well....but it clashes with my presentation :< But guess Chiu Wai, my colleague and Director, can go for that and come back and share instead.<br />
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So sad that I can't take the Mac, I am so absent minded, I better keep things to the minimum....my laptop lasts only 2.5 hours.....haiz. Good thing is....I don't have to work on the plane then. <br />
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<a href="http://www.wcpe2012.org/WCPE_program.pdf">http://www.wcpe2012.org/WCPE_program.pdf</a><br />
<a href="http://www.wcpe2012.org/WCPE_Book_of_abstracts.pdf%20" target="_blank">http://www.wcpe2012.org/WCPE_Book_of_abstracts.pdf </a><br />
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<br />Anonymoushttp://www.blogger.com/profile/01720801784103008765noreply@blogger.com0tag:blogger.com,1999:blog-1726176918632410922.post-37916240461888625182012-03-02T09:04:00.000+08:002012-03-02T09:04:05.304+08:00Making Thinking Visible: Lecture Quizzes My school runs a lecture tutorial system for our Physics Cohort. (We have about 400 to 500 students ....alas....we used to have 800+.....before they stop making Physics a prerequisite for Engineering in Singapore Universities....but that is another story.)<br />
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To let the students pay more attention and consolidate their learning after each topic, we would often give them a lecture tests, not based on complex calculations, rather to assess their basic understanding of the topics.<br />
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The lecture quizzes are traditionally about 5 - 10 multiple choice questions requiring the students to finish in 10 - 15 minutes before the start of the next topic's lecture. The lag is give the students time to read up and consolidate (and actually before the tutorials to make life easier for tutors). They are questions that also require very little calculations.<br />
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Results of lecture quizzes will be given to individual tutors teaching the tutorial classes and the tutors will then run through the problematic areas in class. Tutors traditionally run through the answers before start of the tutorial to just warm up the students and do a quick summary of concepts.<br />
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This year, I decided to try something different. <br />
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1. I did the tutorial questions with my classes first and used the results of the lecture quizzes only at the end of the whole set of tutorial questions (related to the topic)<br />
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2. I captured the responses of all the quiz questions and the final grade separately and did not put them into the original scripts to be returned.<br />
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3. At the last tutorial for the topic, I returned the lecture quizzes (with no ticks or crosses) or grades. Then I gave them 5 min to look through their responses again and pen in their new answers on a separate answer sheet. At this time they are not suppose to discuss with their friends.<br />
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4. Then I gave them 2 min to discuss with their friends where their area of difficult was and write down the new responses again. Finally, think of questions they would like to ask and pen it down. I then collected back the new responses.<br />
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5. The questions were shared in class and discussed together with the answers as a wrapping up activity.<br />
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<br />
After conducting it for a few sessions, I think I will continue to use it in my classroom, cause:<br />
<br />
1. I like the reflective component the activity have.<br />
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2. It did surprised me that there were still concepts the students could not internalise even after going through the tutorials. E.g. for the case of E-field. I realised that Potential concepts were still weak and an area of difficulty even after we have gone through and discussed them. (Remember, I collected the new responses?)<br />
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3. Students through the activity was more aware of where their key areas lie and of course they can allow them to focus more in that particular area.<br />
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4. The activity is also more engaging and promotes active learning, not knowing how well they have done, let's them think more about their answers. <br />
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5. Sharing with their friends, let them learn insights from their friends.<br />
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6. After one or two times, I also find that they start telling me that they realise that getting the concepts is very important, not just focusing on the calculations. Apparently, they thought that if you focused on the calculations in tutorials, the concepts will be internalised naturally. Some reflected that they realised that they need to be aware and be clear on what concepts they are applying or why they are applying it else they could be easily confused by themselves. - This is a leap which I feel was great for me.<br />
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7. The questions being easy and not too complex (in terms of fact that they do not require multiple steps need in calculations) concentrating on simply assessing understand focused key concepts also allow tutors to clearly identify problem areas even after tutorial. Students were truly truly surprised that they could not answer what deceptively looked like straight forward questions that assessed only understanding. (Actually they are the trickest....cause you often cannot plug and chug numbers cause there aren't any.)<br />
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8. Options were carefully designed to identify preconceptions and common misconceptions and hence through the wrong answers, you can tell where should be the area of focus when you revise the topic again or teach this topic again.<br />
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<br />Anonymoushttp://www.blogger.com/profile/01720801784103008765noreply@blogger.com0tag:blogger.com,1999:blog-1726176918632410922.post-44953758260280045122012-01-07T00:07:00.000+08:002012-01-07T16:07:32.880+08:002 Swf to Movie Converter ReviewedAs part of the home-based learning project, I was asked to convert some swf files to movie files so that we could use it for our learning resource.<br />
<br />
In my search on Google, I found two particular ones which some people may use.<br />
<ul>
<li>The first is called SWF to AVI</li>
<li>The second is called SWF to AVI MPEG Converter</li>
</ul>
I installed both on my computer and tried them. Since I have used both of them, I thought I could quickly review them. <br />
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<div style="color: #741b47;">
<span style="font-size: large;"><b>SWF to AVI </b></span></div>
<span style="font-size: large;"><span style="font-size: small;">(At <a href="http://swftoavi.com/">http://swftoavi.com</a>)</span><b> </b></span><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjNq1g8p_RVoEjtUt32x5pGxKZbaU7GkkiAJ3tuVeGx6n6Y326Rn0yN6_WDTpb8PXhHEl1ADWjF_tF1zOAqoNo534OJ2w9Olop5yLUYnPy50MtoszqIBDvriRv4w04w7hxsxn9hPuJiJHo/s1600/swftoavi_small.gif" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjNq1g8p_RVoEjtUt32x5pGxKZbaU7GkkiAJ3tuVeGx6n6Y326Rn0yN6_WDTpb8PXhHEl1ADWjF_tF1zOAqoNo534OJ2w9Olop5yLUYnPy50MtoszqIBDvriRv4w04w7hxsxn9hPuJiJHo/s1600/swftoavi_small.gif" /></a></div>
<div style="color: #cc0000;">
<b>Pros:</b></div>
<ul>
<li>Generally, the software was easy to download, very easy to install.</li>
<li>It was relatively straightforward to use.</li>
<li>The swf I had was interactive, so I managed to capture the clicks the moved on ahead.</li>
<li>Download site was relatively clear and give some instructions on possible problems for sound capture and solution.</li>
</ul>
<div style="color: #cc0000;">
<b>Cons: </b></div>
<ul>
<li>It could only output in AVI format.</li>
<li> I was also visibly disappointed in the poor resolution file it generated.</li>
<li>I read through the sound problem, could not follow through as I could not find the "Wave Mix On" thingy it was describing even after I right clicked. So when I recorded, it seemed to be simply recording what it could of the internal built in microphone. And as there is a construction near my place. I do find it frustrating to hear the background construction noise being recorded as well. But I guess it would be good when you want to record your own voice over the movie file. On hind sight, it could be a configuration problem as I am using a tablet which has a built-in microphone as it has speech to text recognition enabled.</li>
</ul>
<span style="color: #990000;">Conclusion</span>: This could not really served the purpose I wanted as it meant me running through the swf files (since I wanted to capture the clicks) in a sound proof room and it meant me only doing the work in a sound proof room in school, so I abandoned it in the end.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjaJS6U54aMYUAgpbYdbuSVvUtUawhlJjs4JcHFPnWxgniAso_PMLAv1_ppDgTeuMtDlaiGpUotWeQKkNvvBqccLk5tGuAbmx0ASX-zfPIKJhXpLMNuspx7EPqHHBxWvBbhgRe4ocpqDO8/s1600/swficon.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjaJS6U54aMYUAgpbYdbuSVvUtUawhlJjs4JcHFPnWxgniAso_PMLAv1_ppDgTeuMtDlaiGpUotWeQKkNvvBqccLk5tGuAbmx0ASX-zfPIKJhXpLMNuspx7EPqHHBxWvBbhgRe4ocpqDO8/s1600/swficon.jpg" /></a><span style="font-size: large;"><b>SWF to AVI MPEG Converter (Highly Recommended)</b></span><br />
<span style="font-size: large;"><span style="font-size: small;">(<a href="http://www.lumixsoft.com/" target="_blank">http:// www.lumixsoft.com</a>)</span></span><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi20k-iRrNy9YKAwEAON_aW3tXo8yoRkMafKxJ8puSmYjV2p5yERCMcJRZDTRmo3rlV4kxPjk93aKdEFVieoDv8HKBKoSlQTCFlPFjvHsByFG6TydKjqOk9_v-k8_WdGOiPKPu-FShUJIo/s1600/swf2avi_screenshot2.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="193" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi20k-iRrNy9YKAwEAON_aW3tXo8yoRkMafKxJ8puSmYjV2p5yERCMcJRZDTRmo3rlV4kxPjk93aKdEFVieoDv8HKBKoSlQTCFlPFjvHsByFG6TydKjqOk9_v-k8_WdGOiPKPu-FShUJIo/s320/swf2avi_screenshot2.jpg" width="320" /></a></div>
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<div style="color: #cc0000;">
<b><span style="font-size: large;"><span style="font-size: small;">Features:</span></span></b></div>
<ol>
<li><span style="font-size: large;"><span style="font-size: small;"> </span></span><span style="font-size: large;"><span style="font-size: small;">Supports export to AVI, MPEG, MP4 and many other formats.</span></span></li>
<li><span style="font-size: large;"><span style="font-size: small;">As with above, it supports action scripts, movie clips and sound. What I really like is it really captures the narration of my clips but not from the output speaker, cause the sound was clean. For action script, you have an option of clicking, typing the interactive parts of the swf and capture the actions or alternative set to the auto mode which you can set the swf file to advance after the side time if there is no action.</span></span></li>
<li><span style="font-size: large;"><span style="font-size: small;">You can customise the output format (stated above), the parameters (e.g. the frame rate, the size of final video screen.) It does give advice e.g. the screen size, the output platform like ipod, apple TV, DVD that the final file is intended for. Or it can be set entirely automatic.</span></span></li>
<li><span style="font-size: large;"><span style="font-size: small;">The quality of the movie is much better than the above.</span></span></li>
<li><span style="font-size: large;"><span style="font-size: small;">Yes, for ease of use, it is easy to fiddle around, took me about 5 min to figure out how to work through the files.</span></span></li>
</ol>
<span style="color: #cc0000;">Tip:</span> The pause button does not pause the capture, but rather the screen, it was good for me as mine was a Q & A type of swf and so I could control the pause for students to think and then reveal the answer in good time and pausing a longer for the answer if I think my students will need time to digest.<br />
<br />
<span style="color: #cc0000;">Cons: </span> Not any serious one I can think of for the moment. But yes, there are more settings to make than the top, so you need to play around with all the settings for about less than 5 minutes, capture a few trials before you are good to go. Free, bit a logo shows up at the top hand corner of software. But does not really bother me. You can pay and register to get it removed for the export.<br />
<br />
<span style="color: #cc0000;">Conclusion</span>: This is the one I am using, and it is definitely a keeper in time to come.<br />
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<br />Anonymoushttp://www.blogger.com/profile/01720801784103008765noreply@blogger.com0tag:blogger.com,1999:blog-1726176918632410922.post-63667239171994673642012-01-05T12:26:00.000+08:002012-01-06T23:20:33.255+08:00Lesson Activity in MoodleI have just been arrowed a task that was not assigned to me end of last year - to design and build an elesson on the topic of "electricity" for our school's home-based learning.<br />
<br />
Hm...so what is home based learning. It is an initiative that is started by Ministry of Education (Singapore) in response to an incident many years back. In 2003, because of the SARs outbreak, the schools where given sudden notice to close for two weeks. These left the schools in flurry and especially the JCs, as lost in two weeks of precious curriculum had a great impact as the students were expected to sit for the A-levels in two years time. The A-levels was deemed as an important milestone as it meant entrance to university of choice and the subsequent career path that the child would take. So the schools set up contingency plans to get lessons, worksheets and notes delivered to students without face contact.<br />
<br />
The schools in Singapore had been on e-learning bandwagon for some years, but it never really took off as students and teacher still feel it is the face-to-face interaction that is important. Questions and lessons can be modified on the spot based on students' problems and understanding, unlike in the case of elessons, which tend to take a fixed path, and it afterall difficult, even for the most experienced teacher to anticipate every question the children are going to ask.<br />
<br />
Anyway, I have a dateline to meet, was just assigned the task yesterday and I have to get the lesson up by last week of January and first week of Feb, so I am as well get to it.<br />
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<div style="color: #990000;">
<span style="font-size: x-large;"><b>Resources for Learning to Build Moodle Lessons:</b></span></div>
<br />
I have been using Moodle for the last two years and there is one feature that I would very much like to explore. However, as it does take more than a few minutes to learn, so I have never got to learning it. I guess it always boils down to this, there are so many things that we need to do, so we will only go about doing it or learning it when there is a need to. (And that students will only learn things if they find it useful and when they need it. It is the same with upgrading and teaching the skills to teachers, JIT (just in time) teaching are the best. At least, this is what I found that works for staff development in my department. Sharing are just for exposure to ideas and gives you an inkling who to approach. ) <br />
<br />
<br />
So first things first is to look at the possible resources on the Web that allows me to learn Moodle Lesson. Below are some of the ones I really like:<br />
<br />
<br />
<span style="color: #cc0000; font-size: large;"> <a href="http://www.latrobe.edu.au/lms/assets/downloads/moodle/guides/user-guide-lessons_v1.0.pdf" target="_blank">1. "More Moodle - Lessons" by La Trobe University. (Last Accessed: 5th Jan 2012)</a></span><br />
<a href="http://www.latrobe.edu.au/lms/assets/downloads/moodle/guides/user-guide-lessons_v1.0.pdf">http://www.latrobe.edu.au/lms/assets/downloads/moodle/guides/user-guide-lessons_v1.0.pdf</a><br />
<br />
I really like this one, as it explains clearly every step and what every setting the term means though I had a little problem following through as my school is currently using Moodle 1.9 and this version of guide is for Moodle 2.0. We are upgrading to Moodle 2.1 in March....but that would be too late for me.<br />
<br />
Behind this document also states some useful references for learning lessons. I particularly like the videos listed. So I am also linking it here.<br />
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<div style="color: #741b47;">
<span style="font-size: large;">2. YouTube Videos on "Creating a Lesson in Moodle" by LMikowychok</span></div>
<br />
Ah....the wonder of Youtube. You can now find so many video guides to doing so many things and so it is really no wonder. These are a series of 3 videos which will guide you to create lesson in Moodle. It is also good to view it through first to have a rough inkling and overview of what you can do.<br />
<iframe width="640" height="360" src="http://www.youtube.com/embed/c0ewuwDa_O0" frameborder="0" allowfullscreen></iframe>
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<iframe width="640" height="360" src="http://www.youtube.com/embed/O8eO7axqxr4" frameborder="0" allowfullscreen></iframe>
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<iframe width="640" height="360" src="http://www.youtube.com/embed/XR_hrLWtkRE" frameborder="0" allowfullscreen></iframe>
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Happy Moodling!<br />
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<br />Anonymoushttp://www.blogger.com/profile/01720801784103008765noreply@blogger.com0tag:blogger.com,1999:blog-1726176918632410922.post-71345276814250965812011-03-17T15:34:00.000+08:002011-03-18T08:51:38.131+08:00On Nuclear Radiation Part 3: Effects of Different RadiationThis is a third part to a series of FAQs which I received from my friends and family after the Nuclear Accident in Japan Fukushima. <span style="color: #351c75;">Note that most of the notes came from a set of lecture notes that I compiled 2 years ago. The lecture notes were integrated from various sources which was used for lecturing Nuclear Physics for A-levels. </span><br />
<br />
<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhjoA8JlZKY7x038WhMOkEzc3MNk4KrMtrcwSGOiNE7oEzDrokg8m491i627Ew8dRP1bnAEUXDvvybA5X6tg7LpG4tXK73AJPNUNc6EryaJHkHmy3at4D-eiyKqxnAW5KSVjvUASnSgBpg/s1600/r.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="270" r6="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhjoA8JlZKY7x038WhMOkEzc3MNk4KrMtrcwSGOiNE7oEzDrokg8m491i627Ew8dRP1bnAEUXDvvybA5X6tg7LpG4tXK73AJPNUNc6EryaJHkHmy3at4D-eiyKqxnAW5KSVjvUASnSgBpg/s400/r.jpg" width="400" /></a></div>(Picture from Reuters: The No.3 nuclear reactor of the Fukushima Daiichi nuclear plant is seen burning, March 14, 2011. REUTERS/Digital Globe.)<br />
<br />
<span style="color: #cc0000;"><strong>Question: Of the Types of Ionising Radiation, which is the most harmful? How do they affect the human body?</strong></span><br />
<br />
<span style="color: #cc0000;"><span style="color: black;">This is a complex question, as each type of ionising radiation impacts the body differently. In general, the effect of ionizing radiation on the human body or any other living things depend on three things:</span></span><span style="color: #cc0000;"><span style="color: black;"></span></span><br />
<br />
1. The type of ionizing radiation which was absorbed,<br />
2. The number of cells affected, the number and <br />
3. The amount and the rate at which ionizing radiation was absorbed. <br />
<br />
<div> <span style="color: #cc0000;"><span style="color: black;"> Let us look at the effect of each type of ionizing radiation</span></span></div><br />
<ul><li><span style="color: #351c75;"><strong>Alpha-particles:</strong></span></li>
</ul>Even though alpha-particles have a short range in air and can be stopped by the skin or a sheet of paper, it will still pose a danger if it gets into the body through ingestion and inhalation.<br />
<br />
Alpha particles are the largest of the radiation and carry a charge of (+2e) - hence possessing the greatest ionization power, the particles will deposit their energy over a smaller volume (possibly only a few cells) if they enter the body and cause more damage to these few cells.<br />
<br />
Radon gas (one of the key sources of lung cancer in US) is an example of an isotope that radiates alpha particles during of its course of decay and hence, there has been suggestions for buildings to be tested for Radon gas.<br />
<ul><li><span style="color: #351c75;"><strong> Beta Particles:</strong></span></li>
</ul>Beta-particles have a longer range than alpha-particles, but ionise much less strongly. Therefore, they do around 1/20 th of the damage done by the same dose of alpha particles. But with greater penetrating power, affect a greater number of cells.<br />
<ul><li><span style="font-family: "Courier New"; font-size: 10pt; mso-ansi-language: EN-US; mso-fareast-font-family: "Courier New";"><span style="mso-list: Ignore;"></span></span> <strong><span style="color: #351c75;"><span style="mso-list: Ignore;"><span style="font-family: "Times New Roman";"> </span></span>Gamma Rays, X-rays :</span></strong></li>
</ul>Gamma and x-ray are pure energy (photons) and have no mass. They are however very penetrating and can easily pass through the whole body, and hence will still interact with many atoms in the body as they pass through. Both X-rays and gamma rays spread their energy over a large volume, which causes less damage per collision. Of course at very high levels of exposure, they can still cause a great deal of tissue damage. Furthermore, because of their penetrating ability, they can easily reach internal organs and bones which is why large doses can be used to damage cancer tissue. <br />
<br />
<span style="color: #cc0000;"><strong><span lang="EN-GB" style="font-family: "Times New Roman", "serif"; font-size: 12pt; mso-ansi-language: EN-GB; mso-bidi-language: AR-SA; mso-fareast-font-family: SimSun; mso-fareast-language: ZH-CN;">Interaction of Radiation and Cells</span></strong></span><br />
<strong><span style="color: #0b5394;">So how do the radiation affect the cells and human body?</span></strong><br />
The effects of the radiation can be characterised as:<br />
<ul><li>Direct effects</li>
<li>Indirect effects</li>
</ul><strong><u>Direct Effects</u></strong><br />
For direct effects, the radiation interacts with the atoms of the DNA molecule, or some other cellular component critical to the survival of the cell.<br />
<br />
Such an interaction may affect the ability of the cell to reproduce and, thus, survive. If enough atoms are affected such that the chromosomes do not replicate properly, or if there is significant alteration in the information carried by the DNA molecule, then the cell may be destroyed by “direct” interference with its life-sustaining system.<br />
<br />
<strong><u>Indirect Effects</u></strong><br />
However, the probability of the radiation interacting with the DNA molecule is very small since these critical components make up such a small part of the cell. The radiation has a higher probability interacting with the water that makes up most of the cell’s volume.<br />
<br />
When radiation interacts with water, it may break the bonds that hold the water molecule together, producing fragments such as hydrogen (H) and hydroxyls (OH). These fragments may recombine or may interact with other fragments to form toxic substances, such as hydrogen peroxide (H2O2), which can contribute to the destruction of the cell.<br />
<br />
<strong></strong><br />
<strong>In general, the following are possible effects of radiation on the cells:</strong><strong><br />
</strong><strong>1. Cells are undamaged.</strong><br />
Ionisation may form chemically active substances which in some cases alter the structure of the cells. These alterations may be the same as those changes that occur naturally in the cell and may have no negative effect.<br />
<strong><br />
</strong><br />
<strong>2. Cells are damaged, but the damage is repaired and they continue to operate normally.</strong><br />
Some ionizing events produce substances not normally found in the cell. These can lead to a breakdown of the cell structure and its components. Cells can repair themselves if the damage is limited. Even damage to chromosomes is usually repaired.<br />
<strong><br />
</strong><br />
<strong>3. Cells are damaged, repaired but is mutated.</strong><br />
When cells divide to reproduce, an exact copy of the cell's chromosomes are created for the new cell. If the DNA of the chromosome is damaged, the instructions that control the function of the cells and reproduction are also damaged.<br />
<br />
If the cells reproduce instead of die, a new mutated cell may be produced. In many cancers, the instruction that turns off cell growth are somehow damaged causing cells to reproduce out of control, creating tumours. <br />
<br />
Ionizing radiation, along with many other substances such as some chemicals, heavy metals and intense e.m. waves can damage cells in this manner.<br />
<br />
<strong>Radio-Sensitivity of Cells:</strong><br />
Not all cells in the human body respond in the same way to radiation. The most radiosensitive cells are those which :<br />
<br />
*have a high division rate<br />
<br />
*have a high metabolic rate<br />
<br />
*are of a non-specialized type, and<br />
<br />
*are well-nourished.<br />
<br />
<strong><span style="color: #38761d;">Examples of radio-sensitive cells :</span></strong><br />
<br />
*reproductive cells<br />
<br />
*Blood forming tissues<br />
<br />
* Epithidium of skin<br />
<br />
*Epithidium of gastrointestinal tract.<br />
<br />
This is why when people go on radiotherapy, their alocepia (hair loss) tends to occur as hair is a fast growing cell. This also why young children/babies and foetuses carried by pregnant mothers are especially susceptible to radiation. This is because children/babies are growing rapidly, with more cells dividing and thus a greater opportunity for radiation to disrupt the process.<br />
<br />
<span style="color: #cc0000;"><strong><u>Related Links and Previous Related Posts:</u></strong></span><br />
<br />
<a href="http://livingwithphysics.blogspot.com/2011/03/health-hazards-associated-with-nuclear.html"><span style="color: #0b5394;"><strong>1) On Nuclear Physics Part I : What is Radiation? Does a person continue to radiate radiation after he has been irradiated?</strong> </span></a><br />
<br />
<span style="color: #3d85c6;"><strong><a href="http://livingwithphysics.blogspot.com/2011/03/on-nuclear-radiationpart-2.html"><span style="color: #0b5394;">2) Can we therefore make the radioactive isotopes non-radioactive by chemical reactions etc.?</span></a></strong></span><br />
<br />
<span style="color: #3d85c6;"><strong><a href="http://edition.cnn.com/interactive/2011/03/world/interactive.nuclear.japan/index.html?hpt=C1"><span style="color: #0b5394;">3) Japan's Nuclear Concerns Explained by CNN </span></a></strong></span><br />
<br />
<strong><span style="background-color: white; color: #0b5394;">4) </span><a href="http://www.blogger.com/goog_260423799"><span style="background-color: white; color: #0b5394;">Why do the Spent Fuel Rods Need to Be Cooled Down? What happens If they are Not? - External Blog : Fukushima's Spent Fuel Rods Pose Great Dangers.</span></a></strong><br />
<br />
<strong><span style="background-color: white; color: #0b5394;"><a href="http://www.scientificamerican.com/article.cfm?id=pinning-health-problems-nuclear-disaster">5) Scientific American Article : Radiation's Complications: Pinning Health Problems on a Nuclear Disaster Isn't So Easy</a></span></strong>Anonymoushttp://www.blogger.com/profile/01720801784103008765noreply@blogger.com0tag:blogger.com,1999:blog-1726176918632410922.post-56387897715373961272011-03-17T11:54:00.000+08:002011-03-17T11:55:34.915+08:00Japan's Nuclear Concerns Explained by CNN<a href="http://livingwithphysics.blogspot.com/2011/03/on-nuclear-radiationpart-2.html">A CNN Link that explains the concerns of Japan's Fukushima Nuclear Concerns.<br />
</a>Anonymoushttp://www.blogger.com/profile/01720801784103008765noreply@blogger.com0tag:blogger.com,1999:blog-1726176918632410922.post-43400769362010456552011-03-16T17:16:00.000+08:002011-03-16T18:42:36.320+08:00On Nuclear Radiation_Part 2This is a continuation from a previous blog on nuclear radiation.<br />
<br />
<br />
<span style="color: #cc0000;"><strong>I hear that Radioactivty is both a Spontaneous and Random Process, what do the two terms mean? Is there a difference? Can we therefore make the radioactive isotopes non-radioactive by chemical reactions etc.?</strong></span><br />
<br />
Yes, radioactivity is both a random and spontaneous process. Let us explain what it first means to say that it is a "random" process and then talk about the "spontaneous part.<br />
<br />
<strong><span style="color: #0b5394;">Random Process:</span></strong><br />
<br />
By random, we mean that for a sample of radioactive isotopes, we do not know at an instant of time which one will decay. It also means that when we select a particular atom, we do not know when it will precisely decay.<br />
<br />
What is however associated with this process is a probability of decay and that is manifested as what is known as half-life of the sample.<br />
<br />
Beyond the scientific community, it is a common misconception that the half-life of a sample determines the time it takes for it to become non-radioactive.<br />
<br />
This is not true, it is only the time taken for it to decay to half its initial activity. (by layman terms that may be the amount of radiation emitted per unit time.)<br />
<br />
In the case of nuclear waste from nuclear fission power plants, it becomes rather complicated, as the waste product consists of many radioactive isotopes, some ranging to short half lives ( e.g. Iodine-131 ~ 8days) to extremely long half lives ( Tc-99 ~ 220,000 years and I-129 ~ 17 million years).<br />
<br />
There are problems in dealing with the shorter half lives radioactive isotopes and longer radioactive isotopes. In general, the short-lived ones though having a short half live decays rapidly, also emits alot of radiation and that tends to generate alot of energy. This is why in the case of the nuclear accident at Japan, though there are some spent (used fuel ) continuous cooling is needed to bring the temperature down.<br />
<br />
For the case of the isotopes with long half-lives, the activity is smaller but the impact is for a longer period of time, with half lives of 220, 00 years and even million years, this means the radioactive substance will still be emitting radiation many, many years after we have gone. Proper disposal and storage of these waste will therefore be needed as well.<br />
<br />
<strong><span style="color: #0b5394;">Spontaneous Process:</span></strong><br />
<br />
<span style="color: black;">Understanding the spontaneity part will also help understand why we cannot just destroy or hasten or slow down the radioactivity of the radioactive isotopes. Radioactivity comes about because the isotopes are energetically unstable and they try to achieve stability by emitting radiation. It is termed a spontaneous process, as its activity (decay) is unaffected by external pressures, temperatures or any chemical processes. You need time to just let it decay and to come to a stable state.</span><br />
<br />
This is why we also cannot just add chemicals, heat the spent fuel and to treat it to make it safe. You need proper containment procedures to keep it away from possible risks of contamination.<br />
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi8POu2egj-SlSf3WNMTvQ_Lpjgydg6deBSuqnDmywgXK1ehZg8DA7rKlUZ4FpCRGa1w1KaE6Tyh3HfHIjhRHZ5k2OCt7piz3AbxQi5RRF3IBtZVblprNQmePDdEqxQaUS8yBOw4tQSyHQ/s1600/Japannuke.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="260" r6="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi8POu2egj-SlSf3WNMTvQ_Lpjgydg6deBSuqnDmywgXK1ehZg8DA7rKlUZ4FpCRGa1w1KaE6Tyh3HfHIjhRHZ5k2OCt7piz3AbxQi5RRF3IBtZVblprNQmePDdEqxQaUS8yBOw4tQSyHQ/s400/Japannuke.jpg" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Officials in protective gear check for signs of radiation on children who are from the evacuation area near the Fukushima Daini nuclear plant in Koriyama, March 13, 2011. Japanese Chief Cabinet Secretary Yukio Edano confirmed on Saturday there has been an explosion and radiation leakage at Tokyo Electric Power Co's (TEPCO) Fukushima Daiichi nuclear power plant. The biggest earthquake to hit Japan on record struck the northeast coast on Friday, triggering a 10-metre tsunami that swept away everything in its path, including houses, ships, cars and farm buildings on fire. (Kim Kyung-Hoon/REUTERS) <br />
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<strong><span style="color: #38761d;">Other Relevant Links:</span></strong><br />
<br />
<strong><span style="color: #38761d;"><a href="http://livingwithphysics.blogspot.com/2011/03/health-hazards-associated-with-nuclear.html">(1) On Nuclear Physics Part I : What is Radiation? Does a person continue to radiate radiation after he has been irradiated?</a></span></strong>Anonymoushttp://www.blogger.com/profile/01720801784103008765noreply@blogger.com0tag:blogger.com,1999:blog-1726176918632410922.post-62170579195849027522011-03-16T15:58:00.000+08:002011-03-18T08:39:09.945+08:00On Nuclear Radiation_Part 1The Japan's Friday Earthquake and Tsunami has caused Japan's nuclear reactors to malfunction and meltdown, many people may be wondering on the effects of radiation and what harm it may cause and what are the immediate and long term effects.<br />
<br />
I was talking to my husband and a few friends and was surprised to find that they did not know what was radioactivity and the possible health effects (which left me quite frustrated, as I had gone through radiotherapy before and so was very sure that at least my husband should have known the risk that I was exposed to.) Anyway, I took for granted that most people should know, so I was also quite shock when I heard some of questions asked. <br />
<br />
My husband remarked that this was because the biological effects was in the A-level syllabus and I had taught it and so I knew, but I should "enlighten" those who did not take Physics through my blog....anyway I will try my best and present the following as a FAQ in parts. (so that it can be slowly published).<br />
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[I have to note that much of these were taken from a set of lecture notes I prepared for A-levels two years ago and takes references from many websites, so not all the work are my original work, though I consolidated most.]<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg3nJpRh6CmC2tGhYByl0bDjtTA4vgI-m81-x-CBmKmGBxnptsLICvGvFFwSh6jvbr66dFXD_0V3LRpKZhOvRZfaOQxtqGLkXr9R5fZbGH78W9u2IiY2fuN49R_5L8SNLgFSPj_ZRYJy5c/s1600/nuclear1.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="300" r6="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg3nJpRh6CmC2tGhYByl0bDjtTA4vgI-m81-x-CBmKmGBxnptsLICvGvFFwSh6jvbr66dFXD_0V3LRpKZhOvRZfaOQxtqGLkXr9R5fZbGH78W9u2IiY2fuN49R_5L8SNLgFSPj_ZRYJy5c/s400/nuclear1.jpg" width="400" /></a></div><div class="separator" style="clear: both; text-align: center;">(Picture Taken from stock.xchng at <a href="http://www.sxc.hu/">http://www.sxc.hu/</a>. H-Bomb by Sergey Lebedev.)</div><br />
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<strong><span style="color: #cc0000;">What is radiation?</span></strong><br />
The main danger from radiation is the damage it does to the cells in your body. <br />
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Most of this damage is due to ionization when the radiation passes, although if levels of radiation are high there can also be damage due to heating effects as your body absorbs the energy from the radiation.<br />
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<strong>Types of ionizing radiation includes :</strong><br />
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<br />
<ul><li>alpha particles (Helium nucleus)</li>
<li>beta particles (electrons and positrons)</li>
<li>gamma rays</li>
<li>X-rays, and</li>
<li>neutrons</li>
</ul>Alpha and Beta particles are further known as <strong>direct radiation</strong> as they transfer energy directly to their target materials.<br />
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Gamma rays, x-rays, as well as neutrons are known as <strong>indirect radiation</strong>, as they affect the cells in the body by transferring energy to neighbouring atoms. This causes the atoms to become excited and they can produce secondary electrons and photons that can continue to transfer the energy to nearby atoms.<br />
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<span style="color: #cc0000;"><strong>So what are the harms associated with exposure to these radiation? Does a person continue to radiate radiation after he has been irradiated?</strong></span><br />
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To understand this, we need to make distinction between <strong>internal exposure vs. external exposure</strong> as well as <strong>irradiation and contamination.</strong><br />
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<strong><u>Internal Exposure vs. External Exposure</u></strong><br />
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There are two ways in which people can get exposed to radiation exposure :<br />
<ul><li>Internal Exposure,</li>
<li>External Exposure</li>
</ul>o <strong>Internal Exposure</strong> is exposure of radioactive material taken into the body by inhalation, ingestion absorption through skin, or through an open wound.<br />
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o <strong>External Exposure</strong> is exposure of radiation sources outside the body.<br />
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Internal exposure can continue if the radioactive material remains in the body. In contrast, external exposure will not occur again once the radiation has penetrated the body.<br />
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Outside the nuclear and scientific community, there is a general misunderstanding that everything exposed to ionizing radiation is contaminated and dangerous forever. This is not the case, and there is a big difference between something being irradiated and something being contaminated.<br />
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<strong><u>Contamination vs. Irradiation</u></strong><br />
<br />
<span style="color: #134f5c;">o Irradiation:</span><br />
<br />
When something has been irradiated, the irradiation stops as soon as the source of ionizing radiation has been removed. The same can be said about the energy of ionizing radiation.<br />
However even the irradiation has stopped, the biological effects of the irradiation may still occur if un-repaired cell damage has been inflicted.<br />
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o<span style="color: #45818e;"> Contamination:</span><br />
<br />
When contamination occurs, the source of the ionizing radiation itself is transfered, such as when radioactive isotopes in solid, liquid or gaseous forms are introduced into the environment.<br />
When something has been contaminated with radioactive isotopes, it will remain radioactive until the radioactive isotope has decayed to a safe level.<br />
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Hence, from above we see that although one is irradiated by radiation, you do not become radioactive after that and become the source of radiation. This is why food exposed to microwaves do not emit microwave or food that has been treated with X-rays to lengthen their shelf lives are not sources of X-rays themselves.<br />
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However, for the case of Japan, as the nuclear reactors are spewing out particles that are radioactive, the particles can be inhaled by people or get attached to the clothes, the bodies or the vehicles that are passing through. Furthermore, the fall out will land in the water, on the soil etc. Those people and objects that have particles attached to them or have inhaled the particles, consumed the particles or "drank the particles" would therefore continue to emit radiation. This is why people are advised to wear mask and stay indoors. And food from the sources needs to be scanned as the fishes and subsequently the produce may contain high amount of radiation. <br />
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This is the principle we use for carbon dating. Carbon-14 is a radioactive isotope that is continually ingested and inhaled by animals and plants. Due to biological decays and its radioactive decay, the proportion in a living material is more or less fixed and hence there is a stable amount of radiation we emit. When however a living thing die, we stop taking in Carbon-14. That is why the radioactivity reduces and by looking at the reduction, we can date back the once living artifacts to the year it "died".<br />
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<span style="color: #cc0000;"></span><br />
<span style="color: #cc0000;"><strong>I hear that the winds are blowing the steam, the fallout of the explosions into the sea? So is the problem solved?</strong></span><br />
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<span style="color: black;">That depends on how you see it, if the fallout goes towards the sea, the radioactive particles will deposit into the ocean, this means that marine life will get a greater exposure to the radiation and will also ingest a greater amount of radioactive particles. This goes for the same if the steam and smoke gets carried by the winds into the atmosphere, this means the area that is exposed to the radioactive particles are greater but will also mean more distributed and evened out.</span><br />
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Some people are actually hoping for rain, as the precipitation will keep the affected area more confined, but this means the distribution is also more concentrated.<br />
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<span style="color: #76a5af;">Coming up next </span><br />
<span style="color: #134f5c;">(1) </span><a href="http://livingwithphysics.blogspot.com/2011/03/on-nuclear-radiationpart-2.html"><span style="color: #134f5c;">Can we therefore make the radioactive isotopes non-radioactive by chemical reactions etc.?</span></a><br />
<span style="color: #134f5c;">(2) </span><a href="http://livingwithphysics.blogspot.com/2011/03/on-nuclear-radiation-part-3-effects-of.html"><span style="color: #134f5c;">You mentioned alpha particles, but I also know that alpha particle can be stopped by paper,so out of the radiation which is less harmful, and what are the impacts of each type of radiation?</span></a><br />
<span style="color: #76a5af;">(3) Some people say swarthing iodine the bodies will help prevent the radiation from harming the body, is it true? If it is not true, then why are the governments buying iodine pills?</span><br />
<span style="color: #76a5af;">(4) How do we know that a person has been irradiated, are there visible signs e.g. glowing etc? </span><br />
<span style="color: #76a5af;">(5) What are the short term and long term biological effects of exposure to radiation?</span>Anonymoushttp://www.blogger.com/profile/01720801784103008765noreply@blogger.com0tag:blogger.com,1999:blog-1726176918632410922.post-36800529077620513182011-03-15T17:26:00.000+08:002011-03-15T17:33:11.557+08:00A Reading on the History of the Vernier Scale<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhkl18h7is3wUZZUFAV-y6NcCLKLTTs2kNDCHR-UppzjVxFy1ourRJIvF9CIH5_EUSmV0q4OOCnPUoX9vXhHsL5HrlpVNtwj-un8xW8-gOamieOxHm-bKvbTo8m0bRi7lH6YFzg2p-KJ8c/s1600/1172303_97197637.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="265" q6="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhkl18h7is3wUZZUFAV-y6NcCLKLTTs2kNDCHR-UppzjVxFy1ourRJIvF9CIH5_EUSmV0q4OOCnPUoX9vXhHsL5HrlpVNtwj-un8xW8-gOamieOxHm-bKvbTo8m0bRi7lH6YFzg2p-KJ8c/s400/1172303_97197637.jpg" width="400" /></a></div>(Source of picture: <a href="http://www.sxc.hu/">http://www.sxc.hu/</a> by Dora Pete)<br />
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I was doing some readings on American Journal of Physics today and came across an interesting article. Thought that this was rather timely as we had just finished a unit of "Measurements" in A-level Physics at my school. It was would be a good reading for students as it details the historical development of the vernier scale and the vernier callipers happen to be one instrument that students are suppose to know.<br />
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Details of the Article are as follows :<br />
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<strong>Author:</strong> Kwan, Alistair<br />
<strong>Article Name:</strong> Vernier Scales and Other Early Devices for Precise Measurement<br />
<strong>Journal :</strong> American Journal of Physics<br />
<strong>Abstract:</strong> (taken from AJP)<br />
<div class="aip-paragraph">Vernier scales have been extensively used since the 17th century. They replaced the Nonius scale, a unpopular device due to difficulty in its fabrication and use, and they coexisted alongside other types of scales that increased measurement precision and accuracy in complementary ways. The author suggests that the success of Vernier and diagonal scales is due not only to simplicity of fabrication, but also to their exploitation of visual hyperacuities.</div><div class="aip-paragraph"><strong>Access: </strong>Subscription to AJP is needed.</div>Anonymoushttp://www.blogger.com/profile/01720801784103008765noreply@blogger.com0tag:blogger.com,1999:blog-1726176918632410922.post-81319393497936610722011-03-14T19:21:00.000+08:002011-03-14T21:55:19.497+08:00A Peer Rating Form for Lectures<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: left; margin-right: 1em; text-align: left;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiiMKHItaX9bBzAbOEGr8pcMISGMomK-CeORm65K_XdBIL98TsaZOfa2zpzYwjibwg9h2R9Jo7gYAItOC-2N-kAIdilIv_FRz_OAtHdIZshA95IYJBKzyBM6wP3RjuxGgRoAqVnDjGbODY/s1600/PeerAssessment+of+Lecturing+Instrument.JPG" imageanchor="1" style="clear: left; cssfloat: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" height="216" q6="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiiMKHItaX9bBzAbOEGr8pcMISGMomK-CeORm65K_XdBIL98TsaZOfa2zpzYwjibwg9h2R9Jo7gYAItOC-2N-kAIdilIv_FRz_OAtHdIZshA95IYJBKzyBM6wP3RjuxGgRoAqVnDjGbODY/s400/PeerAssessment+of+Lecturing+Instrument.JPG" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Screen shot of Website </td></tr>
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</div>In the beginning of this year, my Level Head paired each of us up during lectures for us to observe each other. At my school, the lectures are distributed amongst the teachers teaching the level and each one of us are given lecture loads which correspond to about two to three topics a year. It is also a requirement for us to sit into the lectures as it serves three purposes - (a) to monitor the students' behaviour and to ensure that they are paying attention in class, (b) to ensure that all tutors are updated on the progress of the lectures and (c) to observe the lecturer. For (c), it serves as a form of professional development for us, as it allows us to further learn what we should do and not do in lectures.<br />
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In the earlier years, as a beginning teacher, I always found it useful and amongst the younger colleagues, we used to ask each other for feedback like "What do you think you like about my lecture?", "Is there anything you think I could have done better?", "Would you have taught it this way?" There were four of us in fact and we used to have these exchanges and enjoyed them thoroughly. No one was ever offended and we would in fact often enjoy the small bickerings on which was a better method. In the process, all of us honestly felt we gained much and learnt alot from each other.<br />
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I do not find this culture prevalent in the younger lecturers anymore. People are not so open to comments or praises, and perhaps this is why my Level Head (who also used to be in our gang of four) has decided to try this peer observation method.<br />
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Anyway, I came across this article while doing research on peer and self rating for teamwork today. It is actually a peer rating form for lectures that was developed by Shapiro Institute for Education and Research at Harvard Medical School and Beth Israel Deaconess Medical Center for their medical lectures.<br />
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It is very well-structured and looks into various aspects of a lecture and what we think should make a good lecture. I feel that this form would also be great for peer observations of lectures in my school or any school that uses the lecture-tutorial system. It provides a good structure on what to look out for in a good lecture and would be a useful formative feedback to the lecturer involved.Anonymoushttp://www.blogger.com/profile/01720801784103008765noreply@blogger.com0tag:blogger.com,1999:blog-1726176918632410922.post-26031775823671186132011-03-08T18:17:00.000+08:002011-03-14T19:29:42.905+08:00Competency Tests in A-level PhysicsAfter teaching for so many years, I would like to consolidate some of the questions and design a series of test to assess my students ability towards A-level physics. This series of tests will be topical based and matched towards the learning outcomes required that for A-levels, I will also identify key skills that would be required each topic and break down the learning outcomes into smaller key concepts. Research on misconceptions will be done for each topic and consolidated. Then I will design questions for each topic.<br />
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I believe this topical tests will be useful for students and teachers. Teachers can use it to assess problems that students may have pertaining to each topic and may design instructional programmes or remediation programmes with further emphasis on the weaker areas that the students may have pertaining to the topic. Students can also use it to assess how well they have learnt a particular topic.<br />
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Since the tests are meant to identify key weak areas, multiple-choice questions will be designed.<br />
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I have started work on the topics and will take about two years to finish. I intend to do reliability and validation studies on the topical tests as well.<br />
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I welcome any feedback to any misconceptions other teachers may have on any topics in A-levels and any suggestions pertaining to what should be placed in the question bank.<br />
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I believe that this test will also be useful for students taking AP (B) Physics and those students in the IB syllabus, with some tweaks as Physics will fundamentally be Physics and there are similiarities to be seen across the syllabi.Anonymoushttp://www.blogger.com/profile/01720801784103008765noreply@blogger.com0tag:blogger.com,1999:blog-1726176918632410922.post-26286604874095204392011-03-08T18:06:00.000+08:002011-03-08T18:06:28.302+08:00Finally Embarking on My ResearchI have been very busy lately as I have started on my research project. Tentatively, I have collected results on the learning preferences of my students as well as results on their knowledge, skills and ability with regards to teamwork and looking the back studies, I think there is very interesting trends I can find.<br />
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I look forward to writing up and consolidating the results next week and finding a journal to publish.Anonymoushttp://www.blogger.com/profile/01720801784103008765noreply@blogger.com0tag:blogger.com,1999:blog-1726176918632410922.post-18014658527247334612010-11-24T15:14:00.000+08:002010-11-24T15:17:20.179+08:00Foresight and Stability of Singapore GovernmentIts been a long time since I updated my blog. Have been very, very, very busy......and was so guilty to take time off to update it.<br />
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Just attended the Singapore Science Teachers' Conference yesterday. No, I am not less busy now....just a little tired....so decided to take a short break to write.<br />
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Had a very interesting talk by a NTU professor in Engineering who shared his insights on his wish list for skills he thought could be taught in Science in school. Another thing he shared were some of the government projects he worked on.<br />
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I was amazed to hear that the Marina Freshwater catchment project's planning and feasibility study had come more than 20 years ago. That implies that the project must have been started some time in the late 80's. The government had worried about the constant threat of the expiration of the water treaty and the constant reliance on water on Malaysia and had been planning for steps on self-reliance. Hence, projects like New Water and also Marina Barrage. I also hear that to also remove reliance on power on Indonesia, the government had been looking at Nuclear facilities and other possibilities of cleaner power some time back and even before it made announcements in 2008 budget.<br />
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I know it sounds a little like propaganda and as if I am a little brainwashed but I cannot help but be impressed with our own Singapore government.<br />
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That brings me to a conversation I had with the Education delegates from Abu Dhabi and UAE when I was at a conference in UK two years back. They had enquired how could our government accomplished so much in so short a time.<br />
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This is my interpretation. We have very passionate leaders in power, people whom I believe fundamentally love the country, and will never want to see it fall. We pay our leaders exceedingly well, so that there is no "excuse" for corruption, and in return the penalty for corruption is exceedingly high till you could possibly lose everything in your whole life and never pick yourself up again (I know it sounds cruel), but there is really no room for mistake. So it is important to juggle this, cause you don't want the wrong people in power.<br />
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Politically, we are very stable. I know some people do criticise the fact that we do not have a "alternative voice". But the political stability is the other crucial factor, with the same party in power - they are able to make long term plans for Singapore. 10 - 20 year plan is not a problem and they know and will be confident that they will see it through. Yes, I do agree that the occasional threats of opposition is good, it keeps our leaders on their toes, but it is definitely an advantage to have a stable group of people overseeing the growth. With long term stability, it is less likely to have leaders who are only concerned about what is in "their" portfolio when they are in term but can also have the capability to have projects that require long term implementation.<br />
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I guess that is what makes a key difference in Singapore. <br />
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Similarly in the educational sector, we also see that many successful school are the traditional schools. You have staff who are alumni, you have principals in power and who fundamentally see their school as their babies, you have people who care about the school and will see the school through both in times of highs and lows. These are the people we want in service and want to make them stay in service. Teaching is therefore not only a job it is a calling, a vocation.Anonymoushttp://www.blogger.com/profile/01720801784103008765noreply@blogger.com0tag:blogger.com,1999:blog-1726176918632410922.post-73431838036448505272010-09-06T21:48:00.000+08:002010-09-08T10:21:22.655+08:00Missing Energy When A Mass is Hung on a Spring?Today we did a very interesting question in class. The question goes something like this :<br />
<br />
<strong><span style="color: #073763;">Consider a light helical spring that obeys Hooke's law. Now, let us hang a mass <em>m</em> on the spring and gently lower the mass till the spring extends to an new equilibrium length. If the net extension of the spring is <em>e</em>, </span></strong><br />
<strong><span style="color: #073763;">(a) What is the loss in the gravitational potential energy of the mass?</span></strong><br />
<strong><span style="color: #073763;">(b) What is the gain the elastic potential energy of the mass?</span></strong><br />
<strong><span style="color: #073763;">(c) Compare the two answers, why are they different?</span></strong><br />
<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhcw2cVx6M_vApFtDjJ1nXBiCnYsQ2jSNmEUsCFiC5D0WfMTSYNdbYW7rS9UKMQtvnaxbWndRbXAgYGiyv_Sv5BlP9BkZv9aNI40iGVQBFHB7LTrzG-2TnhzVX-MugbeDpzarnKBcPeT54/s1600/Mass+on+Spring.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" ox="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhcw2cVx6M_vApFtDjJ1nXBiCnYsQ2jSNmEUsCFiC5D0WfMTSYNdbYW7rS9UKMQtvnaxbWndRbXAgYGiyv_Sv5BlP9BkZv9aNI40iGVQBFHB7LTrzG-2TnhzVX-MugbeDpzarnKBcPeT54/s320/Mass+on+Spring.jpg" /></a></div><br />
Most of the students who did this question, could easily deduce the answers to the first two parts<br />
<br />
(a) The loss in the g.p.e. was <em>mge</em>. and<br />
<div class="separator" style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; clear: both; text-align: center;"></div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none;">(b) The gain e.p.e was 1/2 <em>ke</em><sup>2</sup>. Now, from Hooke's Law, <em>mg</em> = <em>ke</em>. Therefore gain in E.P.E can be written as 1/2 <em>mge</em>.</div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none;"><br />
</div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none;">(c) Comparing the two answers, we see that 1/2 <em>mge</em> went missing.....</div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none;"><br />
</div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none;">Most students at this point in time would then ask two questions. First, "Where did half the energy go to?" the next is that "Is it possible to show that 1/2 the energy would be lost?"</div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none;"><br />
</div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none;"><ul><li><span style="color: #cc0000;">So let us try to tackle the first question: <strong>Where did half the energy go to?</strong></span></li>
</ul></div><span style="color: black;">You see, this in fact a trick question. We only considered the initial state and the final state without considering what happened in between. Consider if the mass as just hung on the spring and allowed to fall without any support. At any point in time, there would have been two forces. (Figure below) The upward force by the spring <em>T</em> and the downward gravitational force <em>mg</em>. </span><br />
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<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEipg2hY3APY5y0N1WJrVWY3eHoY71zL5oP7gpyCIUbdqVJNPEYtI0XzyYuQnAbg6bNKtY0z-2EngHXyYhhOz6NV3wHSrDF8sT_qpAXPnzpwvNWCcJ8chED5uC8SH-fq7d6FEcnJNzf-aJ8/s1600/Mass+on+Spring_Forces.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="200" ox="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEipg2hY3APY5y0N1WJrVWY3eHoY71zL5oP7gpyCIUbdqVJNPEYtI0XzyYuQnAbg6bNKtY0z-2EngHXyYhhOz6NV3wHSrDF8sT_qpAXPnzpwvNWCcJ8chED5uC8SH-fq7d6FEcnJNzf-aJ8/s200/Mass+on+Spring_Forces.jpg" width="142" /></a></div><div class="separator" style="clear: both; text-align: left;">Initially, the spring is unstretched and the mass only experiences a downward force <em>mg. </em>By Newton's 2nd Law, it would therefore also experience a downward acceleration and causes it to gain speed as it moves down. However, as it stretches <em>T</em> increases and the acceleration becomes smaller. Neverthless, before reaching the equlibrium point, it still has a downward acceleration and hence will still gain speed. As it reaches the equilibrium point, <em>T</em> = <em>mg. </em>Although net force is zero, it already has velocity and hence should continue to move down. And as it has velocity at the equilibrium point, it also possesses kinetic energy. And in fact 1/2 of the loss of GPE would hav been converted to E.P.E at that point. </div><div class="separator" style="clear: both; text-align: left;"><br />
</div><div class="separator" style="clear: both; text-align: left;">The trick in this question is therefore, the point that in reality the mass was "gently lowered" to the point of equilibrium and hence there should have been a 3rd external force acting on the system that is doing negative work on the system so that it dissipates the kinetic energy that could have been gained.</div><div class="separator" style="clear: both; text-align: left;"><br />
</div><div class="separator" style="clear: both; text-align: left;">No, conservation of energy was not violated. The loss in GPE was not all converted into Elastic PE of the spring as this was not a closed system, there was an external force acting on the system and it did negative work on the system, dissipating the rest of the energy.</div><div class="separator" style="clear: both; text-align: left;"><br />
</div><ul><li><br />
<div class="separator" style="clear: both; text-align: left;"><span style="color: #990000;">The favourite question by my better students at this point would often be " Would you be able to further convince us that the work done by this force is exactly 1/2 <em>mge</em> as well?"</span></div></li>
</ul><div class="separator" style="clear: both; text-align: left;"><span style="color: black;">Remember, calculus is not a requirement in A-levels, therefore, not to deter my students with the Math, I decide to adopt the graphical approach. (Though calculus is not required, they are expected to know </span></div><div class="separator" style="clear: both; text-align: left;"><br />
</div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg6sYVqerDwOmkNk2T9bOhCvoso0K8eZQPEdc61TlndtcJ4PgLzxA5O1TOAW6oHJWLJsfj16rpvSWV9N8qaktgwLP_p9eeVWxoftcN5mDik61O8yqHOj3yiCD51fwrsakWkqO-oSL6utM0/s1600/integrate+y+with+respect+to+x.png" imageanchor="1" style="clear: left; cssfloat: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" ox="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg6sYVqerDwOmkNk2T9bOhCvoso0K8eZQPEdc61TlndtcJ4PgLzxA5O1TOAW6oHJWLJsfj16rpvSWV9N8qaktgwLP_p9eeVWxoftcN5mDik61O8yqHOj3yiCD51fwrsakWkqO-oSL6utM0/s320/integrate+y+with+respect+to+x.png" /></a></div><br />
is area under the <em>y </em>vs. <em>x</em> graph. Anyway, they have learnt this in their secondary school math as well.)<br />
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So we simplify the problem as such, consider that an external force <em>F</em> acts on the mass (e.g. like a hand) such that it applies a force in such way to lower the mass into the equilibrium so slowly that the mass may be considered to be moving at a constant rate and almost at rest.<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjWDV7DYNhE53ZxfdLSV8lhxSWC1Jqx4O7c29CxBllIYsABieM7540zb5acY81tnpXzOyt_hHKArfiM4qzm4Fweahp4717IzuHTt8x9dd8NAz9oXo0E5qLdg0fUkN6_PPpoFJwCvbQ-Sw0/s1600/External+force+acting+on+the+mass+on+spring.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="142" ox="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjWDV7DYNhE53ZxfdLSV8lhxSWC1Jqx4O7c29CxBllIYsABieM7540zb5acY81tnpXzOyt_hHKArfiM4qzm4Fweahp4717IzuHTt8x9dd8NAz9oXo0E5qLdg0fUkN6_PPpoFJwCvbQ-Sw0/s400/External+force+acting+on+the+mass+on+spring.jpg" width="400" /></a></div>Hence, there are three force <em>T, F</em> and <em>mg</em> on the mass <em>m </em>and <em>F = mg - kx, </em>where <em>x</em> is the extension of the spring. <br />
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The work done by the external force <em>F</em> is therefore the area under the <em>F-x</em> graph. <br />
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Now, from <em>F</em> = <em>mg</em> - <em>kx</em>. The graph of <em>F </em>vs. <em>x</em> is a straight line graph, with y-intercept <em>mg</em> and gradient <em>-</em>k. Sketching the graph, and noting that at equilibrium, <em>F</em> = 0 and <em>x=</em>e<em>. </em>We see that area under the <em>F-x</em> graph which is the work done by F is therefore exactly 1/2 mge. <br />
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<em>F</em> acts in opposite direction to the motion, and hence this work done is actually negative and it seeks to dissipate the kinetic energy that could have been gained.<br />
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Hope this answers the question!Anonymoushttp://www.blogger.com/profile/01720801784103008765noreply@blogger.com0