In order to help students visualise a wavefront, a 3-D image is usually used to show the imaginary line joining particles in phase. I created the Geogebra apps below to allow students to change the wavefront and observe it move with time at a constant wave speed. There represent simplified versions of waves on a

# Author: Seng Kwang

## Graphs of a Progressive Wave - Geogebra App

GeoGebra link: https://www.geogebra.org/m/f7faw3r6 This simple Geogebra app allows students to observe the oscillation of a particle perpendicular to the direction of energy transfer.

## Centre of Gravity and Stability - Geogebra App

This Geogebra app allows students to explore how the position of the centre of gravity as well as the width of its base affect the stability of an object.

## Velocity-Displacement Graph of a Simple Harmonic Oscillator - Animation

This animation is made using Geogebra. It shows the instantaneous velocity and displacement vectors of a particle undergoing simple harmonic motion while tracing its position on the velocity-displacement graph. It is meant to help student understand why the graph is an ellipse.

## Velocity of a Wave - Simulation

Try using the values in this simulation to find the velocity of this wave! Let me have your answer in the comment section! Update on 21 August 2018: The latest iteration of this App is found here:

## Geogebra Simulation for Particle on a Transverse Wave

I am once again exploring the use of Geogebra to create simulations for Physics. This is what I managed to put together. It serves to help students visualise how a particle in a transverse wave moves. The slider allows the user to pick any particle along the horizontal direction of the wave.

## An Aural Illusion for Teaching Frequency and Pitch of Sound

A recent trending phenomenon on the internet is the audio recording of a word, which is interpreted different by two groups of people - those who hear it as "Laurel" vs those who hear "Yanny". To find out which camp you are on, right-click to download this mp3 file and or listen by clicking the

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## Updates

I have not been posting in this blog for a while as I have been rather busy in my new role at the Ministry of Education HQ. My main area of work is related to the Singapore Student Learning Space, an online portal in which curriculum-aligned resources are made available for students in Singapore to

## Water Wheel Challenge

My school organises a competition for upper primary pupils in Singapore annually. Called the THINK Challenge, it gets participants to engage in problem-solving with a little help from the internet, team work and experimentation. "THINK" stands for the stages of the cycle of inquiry learning: Trigger, Harness, Investigate, Network and Know. In this year's Challenge,

## Measuring speed of sound in air using Audacity

A physics demonstration on how to measure the speed of sound in air using Audacity, an open source audio recording software. There are Windows and Mac versions of this free software, and even a portable version that can run off a flash drive without needing to be installed on a computer (for school systems with

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