If the Sun heated our atmosphere and the molecules began spreading apart and rising but our planet's gravity was too
weak to keep them down, what would happen?

the atmospere would drift off into space

none needed

then the molecules would be lost in space

Explanation:

Because if the molecule is spreading and rising and earth's gravity could not hold them down then the molecules would just slip away

the most common energy conversion is from kinetic energy to potential energy, and then from potential energy to kinetic energy.

later on comes the heat energy, mechanical energy, and other energy conversions.

this energy conversion is so common that we can find it in our day to day lives as well.

- one of the most common energy conversions involves the changing of potential energy to kinetic energy or kinetic energy to potential energy