# Month: August 2014

## 5 Strategies to Do Well in JC Physics

1. Make sure that you allocate the same amount of time as you do with other H2 subjects.
This may not mean spending the same amount of time each day, but over the long term, such as the same average time over a week. An over-emphasis on subjects that are perceived as more “challenging” may cause some to neglect subjects that are supposedly “easy to score” when in reality, Physics is not as easy as it was in the O levels. It involves a lot of time spent trying to comprehend concepts (and how they are inter-connected) and practice (just like Maths).

2. Master your Maths
Speaking of Maths, the solving of Physics problems employs a significant amount of Mathematical skills, ranging from basic calculus and trigonometry to vector additions and even arithmetics. You can check the list of mathematical skills needed in the syllabus details (pg 25-26). Examples include sine rule $$(\frac{a}{\sin A}=\frac{b}{\sin B}=\frac{c}{\sin C})$$ and cosine rule ($$a^2 = b^2 + c^2 – 2 bc \cos{A}$$).

3. Start Simple
For students struggling to pass Physics, it might be better for you to start with strengthening your fundamental concepts before moving on to more challenging questions. Take half an hour to make sure you at least understand the worked examples in the lecture notes before attempting the tutorial questions because those are the simplest questions you can get. Diving into the deep end straightaway will only serve to discourage you or worse, “drown” you.

4. Read the Recommended Texts
Make a trip to the library every week to read up on the topic that is being lectured. The list of recommended books should be found in the Scheme of Work given out in the beginning of the year, or downloadable from Matrix. Some of the books recommended for supplementary reading are:

The book “College Physics” by Serway and Faughn may be found on Amazon UK, although I don’t recommend that you buy the books as we have multiple copies available in our library. The books do not cover all the topics in our syllabus as well.

5. Make Your Own Notes

This helps to organise your concepts and draw connections between them. It can be in point form (e.g. list the characteristics of an ideal gas) or in a mind map form.

## How Permanent Magnets Come About

I love the segment about magnetic “domains”. Rule with an “iron fist”. Two of my favourite Youtube channels worked together to make this video.

## Using Socrative for Pop Quizzes

Since almost every student owns a smartphone in SIngapore now, it has become possible for us to gather instant feedback or conduct an on-the-spot formative assessment to identify common misconceptions during class time.

A simple true-and-false quiz conducted during my recent lesson on Gravitation, after the lecture series was completed, showed that students are confused about the different treatment between vectors (force and field strength) and scalars (potential and potential energy).

The questions asked, along with the percentage answered correctly, were:

1. If you were sitting half as far from your nearest classmate, the gravitational force of attraction between the two of you would be four times as strong. (81.0% correct)
2. At the midpoint of the distance from the center of the earth to the center of the moon, the gravitational field strength is zero. (90.5% correct)
3. At the midpoint of the distance between two identical masses, the gravitational potential is zero. (23.8% correct)
4. Work done by gravitational force in bringing an object from infinity to the surface of a planet is negative. (38.1% correct)
5. Satellites in a geostationary orbit must move directly above the equator. (52.4% correct)

This quiz was effective in helping students realise that potential cannot cancel out.

I also took the opportunity to explain to the class why the definition of gravitational potential (as well as potential energy) was based on the work done by an external force, rather than work done by gravitational force.

The tool that I used was Socrative and if anyone would like to use my quiz, you can follow the steps below:

1. Create a teacher account (not a student account) at socrative.com and log in.

2. Click on Manage Quizzes.

3. Select “Import Quiz”

4. Key in the SOC number 12289667

Since you have imported the quiz, you have effectively duplicated the quiz for yourself and are at liberty to edit the questions or even modify the quiz altogether as it does not affect mine.

To conduct the quiz, all you need to do is to go back to the dashboard and click on “Start a Quiz”, selecting the quiz you have saved. Follow the rest of the instructions to select the type of quiz you want (whether at students’ own pace or at a pace determined by yourself).

Once you have started the quiz, get your students to log in at m.socrative.com on their smartphone browsers and key in your Room Number (shown at the top of the screen). You will be able to see the number of students logging in at the top left corner and the attempts of your students in the main area.

If you have any questions regarding the use of Socrative in teaching, feel free to leave a comment below and I’ll try to answer it. Have fun!

## Breaking Glass with Sound

This video shows yet another demonstration for the effect of resonance, when the sound frequency is equal to the natural frequency of the glass. I have yet to conduct this demonstration because of the potential risks involving flying pieces of glass. A video should suffice though, especially one that is taken at slow motion.