Water and Energy

Water can change from one phase to another. These phase changes are determined by the amount of heat energy present. Water in its solid phase (ice) has very little heat energy, compared to the other phases. The molecules are arranged in a pattern and do not move past one another. However, they are not sitting still, they do vibrate in place. In fact, the molecules in an ice cube are vibrating at an average speed of over 50 miles per hour! As heat is added, the molecules move more rapidly and break away from the crystal structure. Molecules can now move past each other. This allows liquid water to flow and take the shape of its container. With the addition of even more heat, water molecules can escape from their container and move very far apart to become water vapor.