Ripple Tank

The rest of the Year 12 Physics class and I were in for a treat last week when we got to see a ripple tank in action. We walked into class on Friday to see a very fancy-looking setup with water, spooky green light and a few electrical components. And it did not disappoint: we let out a collective, “Oooooh” when Dr Doyle turned on the motor.

A mounted light points downwards through a shallow tank of water and onto white paper below. The dark and light patterns on the paper show the crests and peaks of the waves.

After watching the waves for a while, mesmerised, we switched things up. We saw reflection using small sheets of metal and created a gap to see diffraction in action. It was amazing to see the complete change in the wave patterns’ shape. We experimented with different frequencies and different angles of metal. Plus a mini disco party deciding which light colours were best (green and white were winners).

Then we exchanged the single bar attached to the motor for two spheres, creating two coherent sources. Equipped with Dean’s phone catching the waves in slow motion, we observed the constructive and destructive interference that we’d only seen digital simulations of.

All in all, a great chance to put the theory we’ve been learning into practice!

-By Ruby

Photos/video by Ruby, Aadil, Dean