Activity

Marble collisions

Summary
Roll marbles down a U-track and see how energy is transferred as they collide.
Science content
Physics: Motion and Forces, Newton’s Laws, Gravity (K, 2, 6)
Physics: Energy forms, Conservation of Energy (1, 3, 4, 5)
Materials
  • foam pipe insulation ("foam pipe wrap" at Canadian Tire) 6ft by 3/4 inch, split in half (see last photo)
  • masking tape
  • marbles, preferably 4 different colours for each student group
  • optional: Newton's Cradle (ball collision desk toy)
Procedure

Distribute one foam track, masking tape and marbles to each student group. Ask them to tape their track to two desks, so that it hangs down in a U-shape between the desks. Ask them to also tape it to the floor so that it cannot swing.

Students place one marble at the bottom of the track and release another from the top of one side of the track. Watch what happens as they collide.
Record what happens on a worksheet (attached, also a photo), filling in the colours of each marble that they have.
Try with other numbers of marbles at the bottom and being released. The worksheet has suggestions, and leaves spaces for students' own ideas.

Note: I have only tried this with marbles of all the same colour, and the collision happens so fast that some students think that the marbles jump over the ones at the bottom before moving up the other side of the track. With different coloured marbles, I hope that they see that different marbles are bumped up the other side.
Note: if the track is not secured at the bottom, a lot of the energy is lost to the track moving around, and so marbles will not move as high up the other side after the collision.

Discuss their results, and how energy is transferred between the marbles.

Notes

Needs more testing.
Students want to join their tracks to make longer tracks, so do this activity first, then continue to roller coasters.

Grades taught
Gr 3
Teaching site
Carnarvon Elementary