Interesting Video : Newton's Dark Secrets

 

Newton's Laws of Motion together with the study of dynamics forms the foundations of classical physics.  The A-level syllabus and hence the school dedicate alot of the time, especially in the first year in teaching of Mechanics.  My students are always facinated with Newton, his discovery of the three laws and then the Law of Gravitation.  They had also earlier, in their secondary school studied on Optics, where they read about Newton splitting the light into its various colours.  Usually students who do Physics will also do Math and also encounter Newton - Rhapson Method in the approximation of roots.

This "Father of Classical Physics" has therefore also astounded my students with his discoveries.  Sometimes I like to add a little twist to my lessons and therefore, if I have the time, I always like to show this video to my students as it forms a nice ending to especially the study of Mechanics.  My students are always surprised to find that Newton was afterall very human and had weird habits (having an obsession of alchemy and also trying to calculate the end of the world).  Though this video does not show the best side of Newton, it shows his passion and thirst for knowledge had also interest my students to find out more about other Physicists.

A Useful Site for Teaching College Physics: The Physics Source

Today I would like to feature this website known as the "The Physics Source".  It is a featured by Compadre which is also another site which contains very useful resources for students, teachers and faculty members.  However Compadre is a very large site that contains many, many, many other references to sites, so I will rather review each one as I come across.

I particularly like this site as it contains many materials particularly suited for teaching introductory College Physics.  As there are many topics that are also taught in A-levels, the materials can be easily adapted for a A-level classroom.

All the resources are already classified thematically e.g. mechanics.  Under each theme the resources are further classified topically.  Once you enter into the topics, you will have a view of the available resources.  Beyond the title of the resource, there is a brief description on what each resource is and also the weblink to get the resource.

This will definitely be a website I will be visiting see what are the resources available for the topics I am teaching or lecturing.  This is so exciting!

Waves in the Sky - Wave Clouds

[Picture Source:  Compliments of Mr Ong Jek Yaw, 2010]

In the teaching of waves and standing waves, we often use the ripple tank to illustrate phenomenon associated with waves.  Today, I learnt something from a very experienced colleague of mine (Mr Ong Jek Yaw).  In reality, we have an extra large "ripple tank" in our sky!  The rows and rows of clouds that form the sky are in reality known as wave clouds, and they are formed when the atmosphere is disturbed and a "gravity" wave travels through.

From what I understand, wave clouds are form when a thin and stable layer atmosphere is disturbed, e.g. when it passes over a mountain.  The air disturbance can propagate like ripples in the pond when the stone hits the water.  As the wave moves through the air, it undergoes repeated uplift and descent. If there is enough moisture in the atmosphere, clouds will form at the crests of these waves. In the descending part of the wave this cloud will evaporate due to adiabatic heating, leading to the characteristic repeating cloud/clear bands. (wikipedia)

Stationary waves form in the atmosphere can also result in structures observed as well.

Two particularly interesting wave clouds video can be found on youtube and are embedded below:



[ Video above from Youtube, by akrherz at http://www.youtube.com/watch?v=yXnkzeCU3bE]

[Video above from Youtube by RobyF5  at http://www.youtube.com/watch?v=Dvl3PrXwBkI&feature=player_embedded]
More about wave clouds can be found in the links below.

http://www.weatherquestions.com/What_causes_wave_clouds.htm

http://www.theweatherprediction.com/habyhints/64/

http://en.wikipedia.org/wiki/Wave_cloud

http://weathervortex.com/sky-ribbons.htm

Winplot - My Favourite Graphing Software! It is FREE!

In the teaching of physics, it is often that we need to do plots of equations. Many A-level teachers tend to use Excel. This is great when I am creating questions which requires students to take points off graph grids, however, not so great when I just want general (but accurate) shapes to different graphs.

My search of a software became imperative when I was lecturing waves and wanted to generate many different sinusoidal graph starting at different phases. After plotting a few graphs on excel, I gave up and decided to ask a (Further) Math teacher, who told me that she used a free software Winplot.

I have since been using Winplot to generate all my graphs. I found it relatively easy to use for generation of graphs - just type in the equation and the software auto generates for you. You get the flexibilty to change the scale set the thickness and it can be easily copied to the clipboard which can be pasted in any Word document.

It has been almost 7 years since I found Winplot and am still using it. The author constantly makes improvements to it and it is now one of the most powerful graphing software and the great thing is it is still FREE! It is also relatively easy to pick up and there are many external "instructors" that have produced tutorials, manuals, and video instructions.

If you are looking for a free graphing software, this is definitely one to try out.

Most updated version can be found at : http://math.exeter.edu/rparris/winplot.html

A good startoff point for learning are a set of instructional video by Steve Simonds which can be found here : http://spot.pcc.edu/~ssimonds/winplot/

Other supplementary materials can also be accessed here: http://math.exeter.edu/rparris/wpsupp.html

There are some youtube videos as well, one of which is given below.  If you like them, you can google for more at youtube.

A Resource for Teaching Semiconductors: The Solar Cell

An Introduction to Solar Cells

Phys. Teach. 48, 306 (2010)

http://link.aip.org/link/?PHTEAH/48/306/1

[Picture from: http://www.sxc.hu/photo/1054612, johnnyberg, The essens of summer]

The study of Semiconductors and explanation of its behaviour by band theory was introduced into the H2 Physics Syllabus in Singapore for A-level Physics in 2006. Generally, for this topic we learn the mechanics of it, but so far there has been little exploration of its applications in real life.

The May 2010 issue of the Physics Teacher (see link below) carries an interesting article on how solar cells work. It explains the workings of it using band theory as it is a semiconductor. It should find great relevance in today with environmental issues becoming a pressing problem that the world faces.

The link is listed below. I would like to explore how to further apply this article to classroom teaching and integrate this into the A-level syllabus, either as a reading for an activity that can enthuse students or even as an examination question.
The abstract is quoted below:

Abstract : (©2010 American Association of Physics Teachers)

"Most likely, solar cells will play a significant role in this country's strategy to address the two interrelated issues of global warming and dependence on imported oil. The purpose of this paper is to present an explanation of how solar cells work at an introductory high school, college, or university physics course level. The treatment presented here will be qualitative and somewhat simplified, in order to reach the desired audience; references are provided for a more detailed and mathematically sophisticated treatment. It is hoped that this paper will, in a small way, motivate students to learn more about this technology, so critical to the energy and environmental future of this country. "

Popular Science Archive is now free!

My husband and I have always enjoyed Popular Science magazine, and used to be a subscriber till my magazine vendor stop carrying it. It is a great magazine targetted for the layman as it introduces in plain language what are some of the technologies that people are recently developing around the world. Occasionally, I can come across interesting reads that I can use in my lessons.

Good news for all! Recently, Popular Science are partnering with Google to make available their 137 years of archival magazines Popular Science and Popular Mechanics. You can find the archive at http://www.popsci.com/archives.

Or alternatively, you can get both Popular Science and Popular Mechanics in Google Books! I hope this is a trend for magazines to come.

Useful Tool for Drawing 3D - Google sketchup

I was at the Times bookstore last Saturday as it was my birthday month and I wanted to spend away 20% discount card.  I came across a new free tool called Google Sketchup.  It is tool that allows for drawing of 3D diagrams. 

I think that it will be a useful tool for Science Teachers.  If you do a google on sketchup, you can also find many free models for sciences available through the internet.  I have not learnt how to use it yet, but will definitely get to loading and using it.

The tool is available for download at http://sketchup.google.com/