Hot air balloon rises because a) molecules become lighter when heated b) molecules move faster and farther apart when heated c) molecules are less attracted by gravity when heated d) molecules become charged and repel each other when heated

a. molecules become lighter when heated

Reason:

what experimental evidence led scientists to change from the previous model to this one?

a few of the positive particles aimed at a gold foil seemed to bounce back.

the colors of light emitted from heated atoms had very specific energies.

experiments with water vapor showed that elements combine in specific proportions.

cathode rays were bent in the same way whenever a magnet was brought near them.