How would you design a wheeled vehicle to travel the length of a hallway?
This was the challenge for the students in "Cars". The original plan for the three weeks of CARS was to have students investigate vehicles constructed from Thames and Kosmos pieces one week and vehicles constructed from K'nex pieces the next week. In the third meeting, students would build and construct cars of their own design based on what they'd learned the previous two meetings. Mother Nature had other ideas, so only the Wednesday group experienced all three weeks. Nonetheless, we discovered many things about building wheeled vehicles to run well on our particular track system:
Thames and Kosmos cars with a wheel base that fit the track were too top heavy.
Hard plastic wheels did not get enough traction on the floor.
Top heavy cars flipped over.
Cars that were too long dragged on the track.
Cars that were too short flipped over.
Wobbly cars, whose axels could rotate with respect to the longitudinal axis of the car, tended to fall sideways off the track.
Cars whose axels did not stay perpendicular to the track and parallel to each other rubbed against the center guide and didn't roll straight on the floor.
Cars with large wheels in front and little wheels in back flipped over.
Cars with two or four axels rolled better than cars with three.
Adding weight tended to make the car go farther, but too much weight caused it to slow down.
Large and medium diameter wheels were much better than small diameter wheels.
The small diameter wheels needed to be doubled to make them wide enough to stay on the track well.
It was difficult to measure the effect of single variables like weight, wheel diameter, or length because the rigidity of the chassis and ability of the axels to stay aligned was so important.
This was the challenge for the students in "Cars". The original plan for the three weeks of CARS was to have students investigate vehicles constructed from Thames and Kosmos pieces one week and vehicles constructed from K'nex pieces the next week. In the third meeting, students would build and construct cars of their own design based on what they'd learned the previous two meetings. Mother Nature had other ideas, so only the Wednesday group experienced all three weeks. Nonetheless, we discovered many things about building wheeled vehicles to run well on our particular track system:
Thames and Kosmos cars with a wheel base that fit the track were too top heavy.
Hard plastic wheels did not get enough traction on the floor.
Top heavy cars flipped over.
Cars that were too long dragged on the track.
Cars that were too short flipped over.
Wobbly cars, whose axels could rotate with respect to the longitudinal axis of the car, tended to fall sideways off the track.
Cars whose axels did not stay perpendicular to the track and parallel to each other rubbed against the center guide and didn't roll straight on the floor.
Cars with large wheels in front and little wheels in back flipped over.
Cars with two or four axels rolled better than cars with three.
Adding weight tended to make the car go farther, but too much weight caused it to slow down.
Large and medium diameter wheels were much better than small diameter wheels.
The small diameter wheels needed to be doubled to make them wide enough to stay on the track well.
It was difficult to measure the effect of single variables like weight, wheel diameter, or length because the rigidity of the chassis and ability of the axels to stay aligned was so important.