Video Encyclopedia: Move the air track under an air track glider

Video Encyclopedia: Evacuate a glass tube containing water.

A cart is stacked on top of another cart and are coupled together. A rider on the stack of carts is pushed. Once the carts are up to speed they are uncoupled just before striking an object that stops the lower cart. The top cart continues at the same speed as before the impact. The lower cart stops due to an external force.

Video Encyclopedia: Hit a real rock and then a foam rock with a heavy mallet.