My Sims & Videos

1. Measurement

2. Kinematics

Free-fall of basketball
Suitable for video analysis (each floor is 3 metres), youtube link is here.

Independence of horizontal and vertical motion in projectile
Youtube link is here.

3. Dynamics

  • Newton's 2nd Law (Completed together with my CID4 students) (.jar simulation file here)

What happens when you drop a spring balance with the measured object still on it?
This video (shot at 120 frame-per-second) can be used to show that the spring balance does not measure the weight/gravitational force of the object hanging below rather it is measuring the force exerted by object.
  • The spring extends because the object exerts a force on the spring balance and the spring balance exerts an equal force on the object (Newton's 3rd Law). The force on the object exerted by the spring balance is equal to the gravitational force on the object when the system is in equilibrium (either at rest or at constant velocity).
  • When the system is accelerated (or free fall in this video), the force exerted on the spring balance by the object is different (zero at free fall) while the gravitational force on the object remains constant

4. Forces

Wheels on shopping cart
This is something that should be related to your experience when shopping with your family at supermarkets, etc. Observe the behaviour of the wheels and provide your explanation. Youtube link is here.

Tipping Buckets
What causes the bucket to tip? Youtube link is here.

5. Work, Energy and Power

6. Motion in a Circle

Video on newton's 1st law in circular motion
Youtube link is here.

7. Gravitational Field

  • Field strength, potential and potential gradient for 1 or 2 planets (.jar simulation file here)
  • Refer to figure below and suggest your responses to the following questions:
    • Explain why the potential graph has (i) a maximum and (ii) why the curve is asymmetrical.
    • Why is the gravitational field strength around the two masses is sometime positive and sometime negative?

  • Satellite around Earth (require Java 3D installed) (There are 2 sim files - older version for some computers and latest version) created by Wee Loo Kang
  • Refer to figure below and suggest your responses to the following questions:
    • Explain why some satellite are not consider geostationary.
    • Some of the situations are not even possible physically.
    • What do you understand about polar orbit?

  • Kepler's 3rd Law (not my sim but very nicely done to illustrate T^2 proportional to r^3)

8. Oscillations

  • Vertically oscillating spring-mass system (N08/III/6) (Download simulation and run in your browser, Source file here, ejss reader file here) - This simulation was created with input from Mr Ng Kar Kit from River Valley High School
A spring has an unstretched length of 0.650 m is attached to a fixed point. A mass of 0.400 kg is attached to the spring and gently lowered until equilibrium is reached and the spring is stretched elastically by a distance of 0.200 m. The load on the spring is set into simple harmonic motion of amplitude 0.200 m.

The energies against displacement (taking upward displacement from the equilibrium position as positive) is plotted beside the simulation.

The gravitational potential energy is calculated with respect to the reference level (blue horizontal line). This reference level can be adjusted by (1) dragging the blue box at the right end of the reference level or (2) entering the value of the position in the text box at the lower right hand corner.

  • Coupled pendula (.jar simulation file here)

9. Thermal Physics

10. Wave Motion

  • Transverse wave and phase (without circle to show the phase) (.jar simulation file here)

  • Propagation of circular wavefront from a point source (.jar simulation file here)

11. Superposition

Superposition of pulses

Single Slit Diffraction 
Modified from Wee Loo Kang's simulation to reduce the complexity of the user interface to enhance learning (.jar simulation file here)

Two source interference 
Modified from our edulab project virtual lab simulation to reduce the complexity of the user interface to enhance learning (.jar simulation file here - work in progress, may be unstable)

Young double-slit experiment

Simulation is based on earlier related EJS models by Wee Lookang, Andrew Duffy, Juan M. Aguirregabiria and Fu Kwun Hwang. (.jar simulation file here, weblink here)

Quantum Physics

Line Spectral with Tracker
Created this instructional video on "using Tracker for spectroscopy". Youtube link is here.

Lessons that took place before this activity Students could have
  • observed the emission spectrum of elements such as sodium, neon, mercury, kryption, etc. although they do not have hands-on experience of setting up and adjusting the apparatus.
  • gone through the theory and tutorial on the section of spectral lines.
Below is the worksheet that students will attempt.

Pictures of the solar spectrum and the emission spectrum of different elements (derived from the picture here and here).
Disadvantages of hands-on approach
  • Experiments on spectral lines are time consuming due to the difficulty in setting up and calibrating the spectrometer.
  • The other big challenge is the availability of a suitably dark room to observe the emission spectrum of discharge tubes.
  • The availability of sufficient apparatus for experiments.
Advantages of using Tracker
  • Cheap.
  • Easy to deploy.
  • Easy to operate to obtain quality results for comparison and analysis because students  can now focus on the actual physics rather than on the setting up of the experiment.