Physical Science

Matter can exist in four phases (or states), solid, liquid, gas, and plasma, plus a few other extreme phases like critical fluids and degenerate gases.

 

SOLID:

 A solid is matter in which the molecules are very close together and cannot move around. Examples of solids include rocks, wood, and ice (frozen water). 

 

LIQUID: 

A liquid is matter in which the molecules are close together and move around slowly. Examples of liquids include drinking water, mercury at room temperature, and lava (molten rock).

 

GAS: 

A gas is matter in which the molecules are widely separated, move around freely, and move at high speeds. Examples of gases include the gases we breathe (nitrogen, oxygen, and others), the helium in balloons, and steam (water vapor).

 

PLASMA:

 A plasma is a gas that is composed of free-floating ions (atoms stripped of some electrons - positively charged) and free electrons (negatively charged). A plasma conducts electrical currents