Teaching Resources

Physics teaching resources

02 July

Phase Difference GeoGebra Apps

Seng Kwang Tan 11 Wave Motion, 12 Superposition, GeoGebra 0 Comments

I created a series of GeoGebra apps for the JC topics of Waves and Superposition, mainly on the concept of Phase Difference. The sizes of these GeoGebra apps are optimised for embedding into SLS. When I have time, I will create detailed instructions on how to create such apps. Meanwhile, feel free to use them.

Instructions on how to embed the apps into SLS can be found in the SLS user guide.

Phase difference between two particles on a progressive wave. Move the particles along the wave to see the value.

Phase difference between two particles on a stationary wave. Move the particles along the wave to observe how their velocities are different or similar.

Observe velocity vectors of multiple particles on a progressive wave.

24 May

Javascript Game to Learn How to Count Money

Seng Kwang Tan Games 2 Comments

Trying to brush up my Javascript skills after being inspired by one of the senior specialists in ETD, I created this simple Javascript Game to teach kids how to count money using Singapore coins.

To play this game, click or press the “Play Button”. Click on the coins to make up the targeted amount. Be careful as the coins will move over one another.

This is meant for children entering primary one soon so that they can learn how to pay for food at the canteen.

To insert this into SLS, download the zipped file here and upload as a media object.

30 December

GeoGebra in SLS

Seng Kwang Tan GeoGebra, Teaching Resources 0 Comments

Useful Links for Learning about using GeoGebra in SLS.

  1. Instructions on how to embed GeoGebra into SLS via iframe (recommended) (Method 1).
  2. Instructions on how to upload GeoGebra into SLS as a standalone package (Method 2).
  3. GeoGebra apps curated for A-level Physics: https://www.geogebra.org/m/dgedzmz3
  4. GeoGebra apps curated for O-level Physics: https://www.geogebra.org/m/z5nfs8qd
  5. Using GeoGebra Group as an LMS.
  6. IPSG Poster on “An SLS Learning Experience with GeoGebra Apps on the First Law of Thermodynamics”. Update on 2 Jul 2019: The SLS lesson shared during IPSG 2019 can now be found in the SLS Community Gallery.
  7. Let us know if you have used or adapted the SLS lesson, or if you have ideas for new GeoGebra apps in the comment section below.

21 October

Idealized Stirling Cycle

Seng Kwang Tan 09 First Law of Thermodynamics, GeoGebra 0 Comments

I created a new GeoGebra app based on an ideal Stirling Cycle (A. Romanelli Alternative thermodynamic cycle for the Stirling machine, American Journal of Physics 85, 926 (2017)) which includes two isothermal and two isochoric processes. The Stirling engine is a very good example to apply the First Law of Thermodynamics to, as the amount of gas is fixed so the macro-variables are only pressure, temperature and volume. Simplifying the cycle makes it even easier for first time learners to understand how the engine works.

For those who prefer to be impressed by an actual working model, it can be bought for less than S$30 on Lazada. All you need for it to run is a little hot water or some ice. Here’s a video of the one I bought:

The parts of the Stirling engine are labelled here:
How a Stirling Engine works

My simulation may not look identical to the engine shown but it does have the same power piston (to do work on the flywheel) and displacer piston (to shunt the air to and fro for more efficient heat exchange).

Geogebra link: https://www.geogebra.org/m/pbnw2yas

23 September

Geogebra App on Maximum Power Theorem

Seng Kwang Tan 15 DC Circuits, GeoGebra 0 Comments

GeoGebra link: https://www.geogebra.org/m/hscshcj8

This simulation demonstrates the power dissipated in a variable resistor given that the battery has an internal resistance (made variable in this app as well).

Since the power dissipated by the resistor is given by

[latex]P=I^2R[/latex]

and the current is given by

[latex]I=E(R+r)[/latex],

[latex]P=E^2\times\dfrac{R}{(R+r)^2}=\dfrac{E^2}{\dfrac{r^2}{R}+R+2r}[/latex]

This power will be a maximum if the expression for the denominator [latex]\dfrac{r^2}{R}+R+2r[/latex] is a minimum.

Differentiating the expression with respect to R, we get
[latex]\dfrac{d(\dfrac{r^2}{R}+R+2r)}{dR}=-\dfrac{r^2}{R^2}+1[/latex]

When the denominator is a minimum,
[latex]-\dfrac{r^2}{R^2}+1=0[/latex]

Therefore,
[latex]r=R[/latex] when the power dissipated by the resistor is highest.