Quincy is standing in a field holding a balloon on a string. The balloon is filled with helium and is floating above his head. If Quincy lets go of the string, what happens to the balloon and why? Respond very briefly.
The balloon rises upward after Quincy lets go of the string. This happens because helium is lighter than air, which makes the balloon buoyant. As a result, the balloon displaces air and is pushed upwards by the denser air around it, which is an application of Archimedes' principle concerning buoyancy. The force of gravity is weaker on the helium balloon compared to the surrounding air, causing the balloon to rise until the surrounding air becomes equally as thin as the helium inside the balloon.