- x vs t graphs
- v vs t graphs
- Verbal descriptions (I called them textual descriptions in the first class today, and got the expected chorus of giggles, so I gave up on that)
- Algebraic models (equations)
The best way to do it is to do it, so they jumped in and formulated their own questions about the two constant velocity buggies that I gave them; I took out one battery from the red one and replaced it with a strip of copper to make it run significantly slower. They were the equipment; the question was "what can you do with this?"
They came up with great questions - some were classics, and some were a little more out-of-the-box. All let them test their diagramming and algebraic problem-solving chops:
- Cars facing each other - "where/when will they collide?"
- Cars starting apart - "when/where will one car pass the other?"
- Cars starting together, facing away from each other - "when will they be 10 m apart?"
- Cars starting together - "when will one car have gone twice as far as the other?"
This is a strange result indeed - no reference to time or distance! The interpretation: if they really do start at the same spot, the question can only be answered if the faster car has twice the speed of the slower car. If it does, then any time or distance works. If not, no time or distance works!