When I teach refraction in my optics unit I find the students have a really hard time understanding why the waves change direction. I explain that it’s because one side starts moving slower relative to the other causing it turn, similar to what occurs when a car has its two right wheels on the shoulder. This analogy is hard for them since most don’t drive yet. This year I decided to do something different and since students love visuals and demonstrations, I came up with one that turned out to be very successful. Please keep in mind this is an initial activity which took place before we had started refraction.
– 1 scooter
I took a scooter without modification and sent it on its way. It traveled in a straight line (see video below).
Before doing anything more I asked my students why the scooter moved in a straight line. Eventually we got to the correct answer that all four wheels were moving at the same rate. I then asked them what they thought would happen if I put tape on the two right wheels of the same scooter. I then sent it on its way and it went careening into the wall, similar to how a car can react if you start driving on the shoulder.
We then discussed as a class the reasoning behind the altered motion of the scooter.
An excellent learning experience through inquiry and observation. I found a deeper level of understanding following this demonstration then I have seen in the past through explanation.
Classroom Connections: Please click below to view a sample of my Refraction Lessons and/or Optics Unit.