Technology

06 December

Vertical Non-Uniform Circular Motion

Seng Kwang Tan 06 Motion in a Circle, GeoGebra, Simulations 0 Comments

This is a simulation that shows the vectors of forces acting on an object rolling in a vertical loop, assuming negligible friction.

To complete the loop, the initial velocity must be sufficiently high so that contact between the object and the track is maintained. When the contact force between the object and its looping track no longer exists, the object will drop from the loop.

The following code is for embedding in SLS.

<iframe scrolling="no" title="Vertical non-uniform circular motion" src="https://www.geogebra.org/material/iframe/id/ny3jhhsp/width/640/height/480/border/888888/sfsb/true/smb/false/stb/false/stbh/false/ai/false/asb/false/sri/true/rc/false/ld/false/sdz/false/ctl/false" width="640px" height="480px" style="border:0px;"> </iframe>
01 December

Hydrostatic Pressure and Upthrust

Seng Kwang Tan 04 Forces, GeoGebra, IP Topics, Simulations 0 Comments

This app is used to demonstrate how a spherical object with a finite volume immersed in a fluid experiences an upthrust due to the differences in pressure around it.

Given that the centre of mass remains in the same position within the fluid, as the radius increases, the pressure due to the fluid above the object decreases while the pressure below increases. This is because hydrostatic pressure at a point is proportional to the height of the fluid above it.

It can also be used to show that when the volume becomes infinitesimal, the pressure acting in all directions is equal.

The following codes can be used to embed this into SLS.

<iframe scrolling="no" title="Hydrostatic Pressure and Upthrust" src="https://www.geogebra.org/material/iframe/id/xxeyzkqq/width/640/height/480/border/888888/sfsb/true/smb/false/stb/false/stbh/false/ai/false/asb/false/sri/false/rc/false/ld/false/sdz/false/ctl/false" width="640px" height="480px" style="border:0px;"> </iframe>
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.

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