The New Childrens Encyclopedia

224

SOLID STATE

The atoms or molecules in a solid substance

are held together by electrical forces. They

are arranged in a repeating pattern called a

crystal lattice—similar to the way apples or

oranges stack together in a grocery store.

This makes the solid dense and hard.

SCIENCE

Solid, liquid, or gas?

Almost everything in the world exists in one of three states

of matter. Solids keep a fixed shape, liquids have no fixed

shape but fill the container in which they are held, and

gases float around in space with no fixed shape or volume.

Carbon crystals A diamond is made up of

many carbon atoms, which line up to form a

crystal. The arrangement is so perfect that the

carbon atoms are held very tightly. This makes

diamond the hardest substance found in nature.

LIQUID TO SOLID When the molecules in liquid

water lose energy, they freeze and turn into solid ice.

Water freezes at 32°F (0°C).

SOLID TO LIQUID If you heat up an ice cube to its

melting point, the solid ice gradually turns into liquid

water. Ice melts at 32°F (0°C). Melting

Freezing

 LIQUID The atoms

or molecules in a liquid

are packed less tightly

than those of a solid.

 SOLID The atoms or

molecules in a solid are

packed tightly together.