Glossary: alcohol

A chemical substance found in beer, wine, and liquor, and some medicines, mouthwashes, household products, and essential oils (scented liquid taken from plants). Alcohol contains a carbon atom attached to a hydroxyl group (a molecule made of an oxygen atom and a hydrogen atom).

The smallest part of a substance that cannot be broken down chemically. Each atom has a nucleus (center) made up of protons (positive particles) and neutrons (particles with no charge). Electrons (negative particles) move around the nucleus. Atoms of different elements contain different numbers of protons, neutrons, and electrons.

A substance made up of elements, such as hydrogen or sodium.

The smallest particle of a substance that has all of the physical and chemical properties of that substance. Molecules are made up of one or more atoms. If they contain more than one atom, the atoms can be the same (an oxygen molecule has two oxygen atoms) or different (a water molecule has two hydrogen atoms and one oxygen atom). Biological molecules, such as proteins and DNA, can be made up of many thousands of atoms.

A colorless, odorless gas. It is needed for animal and plant life. Oxygen that is breathed in enters the blood from the lungs and travels to the tissues.