Advanced 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.

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.

Topic 1 Measurements

The topic of measurements consists of 4 main subtopics:

1.1 Physical Quantities and Units
1.2 Errors and Uncertainties
1.3 Scalars and Vectors
1.4 Orders of Magnitude

1.1 Framework of Concepts and Skills for Physical Quantities and Units

1.2 Errors and Uncertainties- 2 Feb 2015

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.

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.  

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.

1.3 Vectors and Scalars - 2 Feb 2015

01 Units and Measurements: Teaching Resources

Introduction:
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.

Topic 1 Measurements

 1.1 Physical Quantities and units

Possible Lesson Flow

12 Jan 2015

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.

Lecture Outline

1.  What is Science and Physics ?

• systematic enterprise (scientific method)
• testable explanations + predictions -> experimentation.

2.  What is Scientific method:

• Based on observations forming testable hypothesis -> predictions which is testable by experimentation.
• After many cycles of experimentation if the hypothesis works then we form theories.
• Arthur used a very interesting example of apple falling from tree and an invisible string that holds the apple to the Earth.

3.  What do we do in experimentation?

• Measure (apparatus) / Calculate and collect and analyse scientific data and reach conclusions

4.  Physical Quantities and Units

• Many of the data that we collect in physics are quantifiable.
• Brings us to what is a physical quantity.  
• What can we do with physical quantity :
• Law of Homogeneity of equations can be introduced here.
• Comet and probe exercise on what physical quantities are we interested in.

 Video Resources:

 Video 1 :  Redefining the mass (1 kg) - the roundest object on earth.

•  A beautiful video to be used on teaching the base quantities and units.
• Discusses about how calibration standards change.
• 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.

A Reading on the History of the Vernier Scale

(Source of picture:  http://www.sxc.hu/ by Dora Pete)


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.

Details of the Article are as follows :

Author:  Kwan, Alistair
Article Name:  Vernier Scales and Other Early Devices for Precise Measurement
Journal :  American Journal of Physics
Abstract:  (taken from AJP)

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.

Access:  Subscription to AJP is needed.