In year 2 we have made in class our own version of the activity proposed in the following CD ROM:
We are trying to check which cars will travel furthest: those with big sized wheels or those with small ones. First, of course, we made a prediction. Then, we threw the cars down the slope. In the picture you can see how far they moved.
According to our experiment, the car that went furthest had small wheels. However, after checking the results in VIRTUAL EXPERIMENTS, we have realised that our results are not relaible. Cars were different sizes and we did not have the opportunity to use the same car with different sized wheels.
The car with the biggest wheels will go furthest. The reason is that big wheels have less surface in contact with the ground and, as a consequence, there is less friction.
In the following video you can see that rollerblader know that: if they want speed, they use big wheels, if what they want is easy maneuvering, they choose small wheels...
We have really enjoyed our experiment. Hope you also enjoy!