The potential energy in molecules is stored in...

Energy, potential energy, is stored in the covalent bonds holding atoms together in the form of molecules. This is often called chemical energy. Except at absolute zero (the coldest temperature it is possible to reach), all molecules move.

Chemical energy

Explanation:

Energy, potential energy, is stored in covalent bonds holding atoms together in the form of molecules

the dependant variable is spilled water

the independent is the heat