Copyright © 2007 Dorling Kindersley
Dust, living things, oceans, mountains, and planets—everything you can touch is made from matter. With electron microscopes, scientists can see that all matter is made from particles—tiny specks of matter that stick together like crystals in a cube of sugar.
All matter in the Universe was created by the Big Bang 14 billion years ago. In less than a second, the Universe was filled with vast amounts of energy, such as light and heat. The explosion made the Universe expand. As it expanded, it cooled, and particles with MASS formed and clumped together.
Most matter on Earth exists in one of three states—solid, liquid, or gas. In a solid, the particles are packed closely together in a rigid pattern. In a liquid, the particles are touching, but tumble freely over each other. In a gas, the particles are widely spaced and move around at random.
Matter is built from particles. The smallest particles are fundamental particles. Scientists have discovered two kinds of fundamental particles—quarks and leptons. Evidence for quarks and leptons is found by smashing together larger particles at very high speeds. The particles split and new particles are formed.
Mass is the amount of matter an object contains. All objects with mass have inertia (a force is needed to start, stop, or change their motion), and are attracted to each other by the force of gravity.