Guided Inquiry and Momentum

I chose the question: How does steepness of a slope and mass affect a collision outcome? My plan was to let a Hot Wheel car roll down a ramp and collide with a marble at the bottom, and then measure the distance the marble rolled. The experiment would be repeated with the three marbles of different masses--a small, medium, and large. I would then make my ramp steeper and repeat the experiment. My hypothesis was that the steeper the ramp the more velocity and the further the marble would roll. The more mass the marble had the less distance it would roll.
With two toddlers in the house and cars involved, it became a family experiment. It took some trial and error before we found the right combination of ramp material and Hot Wheel car that would go down the ramp in a straight enough line to hit the marble at the bottom. We rolled the car down the ramp three times for each size marble and measured the distance it rolled. We then raised the ramp height and repeated the experiment. (My kids had a grand time and were very involved--showing that such projects can be engaging and even exciting).
Our experiment proved my hypothesis correct. I was surprised at the difference traveled by the marbles. The smallest marble went way further than the large one, by about 100 cm.
I wonder if we should have used a different object than marbles--something that would not have rolled. If I were to use this in the classroom, I would use something other than marbles as they rolled quite far and would be a challenge to follow and measure the distance traveled without crossing the paths of others, or running out of room for several groups to be working.
To make it more engaging, there could be a competition as to which group could get the object to go the farthest. They could also add mass to the cars going down the ramp.
To connect to student lives, we could make the connection to playing football--it takes more force to move a larger player and stop a larger player.
We could also talk about car crashes--the faster one is traveling; the more damage done to the car, the object hit, and the people involved.
If I did this experiment with students I would hope they would learn more about how velocity and mass are related to momentum--that it takes more velocity and mass to move larger objects. The slower the velocity the less of an impact and the less momentum.
Did I achieve this goal? With me, it solidified these concepts. I believe it would help students as well.