Zephyr is standing on the ground holding a balloon on a string. The balloon is filled with helium and floating above Zephyr's head. If Zephyr lets go of the string, what will happen to the balloon, and why? Provide a very short response.
The balloon will rise upwards after Zephyr lets go of the string. Helium is lighter than air, giving the balloon buoyancy, which causes it to float. When the string is released, there is no longer anything anchoring the balloon to Zephyr's position, so the force of buoyancy will carry the balloon upwards into the sky.