Atoms and Molecules

What are books made of? What are computers made of? Everything around you is made of atoms and molecules. Molecules are the smallest particle of matter that can exist and still have all the properties of a particular object. But what is the difference between atoms and molecules? Well, atoms are what make up molecules.

Molecules are always moving , but when an object is heated its molecules moves faster and farther apart. When an object is cooled its molecules move slower and closer together. In a solid the molecules are tightly packed together in a fixed position. But when a solid is heated the molecules move farther apart and go from a solid state to a liquid state which is called melting.

In a liquid molecules move faster and more freely than molecules in a solid. When heat is added to the water the molecules move even faster and bump into to one another. Some of the molecules ar pushed out in to space and become a gas. This is called evaporation.

In a gas, the molecules are very far apart and move freely in space. The process of boiling water and changing it quickly into a gas is called rapid evaporation.

What do molecules have to do with heat transfer? Even if it is snow, the more molecules the more heat. For example, an ice sculpture has more heat than a match. Why? Try melting a whole ice sculpture with one match. Which one last longer?