A-level Topics

Explanation for Water Bending with Static Electricity

It’s interesting to note the differing views regarding the explanation for how a thin stream of water can get bent when a charged object is placed near it. It started with these two videos from Veritasium:

This video then sets out to disprove Veritasium’s model of ions being removed from the water stream.

Simulation for Gravitational Field Strength and Potential

This simulation allows students to observe the variation of gravitational field strength and potential between two masses. Field strength is shown as vectors whereas potential is shown as scalar values on a plot. The resultant field strength and potential are shown in red.

https://ejss.s3.ap-southeast-1.amazonaws.com/gravitation_Simulation.xhtml

Man in Elevator Simulation

man_in_elevator_simulation

In this simulation, students can observe the variation of the normal contact force (N) and its effect on acceleration and velocity as an elevator moves upward.

Questions for students to work on can include:

  1. Express the acceleration as a function of Normal Contact Force (N), Weight (W) and mass of the man.
  2. Determine the distance travelled by the elevator.
  3. Predict how the forces, acceleration and velocity will differ if the elevator was moving down instead.

Internal Resistance and Maximum Power Theorem

I’ve created this simulation to demonstrate the effect of an internal resistance due to a cell on the potential difference and current of an external load.

One can also vary the internal resistance and external resistance to observe the maximum power theorem. The theorem states that for a given finite internal resistance, one can obtain the maximum external power only when the resistance of the load is equal to the internal resistance of the source.

internalresistance

https://ejss.s3.ap-southeast-1.amazonaws.com/internalresistance_Simulation.xhtml