States of Matter.

Different States of Matter.

In physics, a state of matter is one of the distinct forms that matter takes on.

Four states of matter are observable in everyday life: solid, liquid, gas, and plasma.

Many other states are known, such as Bose–Einstein condensates and neutron-degenerate matter, but these only occur in extreme situations such as ultra cold or ultra dense matter.

Other states, such as quark–gluon plasmas, are believed to be possible but remain theoretical for now.


Solid.

In a solid the particles (ions, atoms or molecules) are closely packed together.

The forces between particles are strong so that the particles cannot move freely but can only vibrate.

As a result, a solid has a stable, definite shape, and a definite volume.

Solids can only change their shape by force, as when broken or cut.


Liquid.

A liquid is a nearly incompressible fluid that conforms to the shape of its container but retains a (nearly) constant volume independent of pressure.

The volume is definite if the temperature and pressure are constant.


Gas.

A gas is a compressible fluid.

Not only will a gas conform to the shape of its container but it will also expand to fill the container.


Plasma.

Like a gas, plasma does not have definite shape or volume.

Unlike gases, plasmas are electrically conductive, produce magnetic fields and electric currents, and respond strongly to electromagnetic forces.

Positively charged nuclei swim in a "sea" of freely-moving disassociated electrons, similar to the way such charges exist in conductive metal.

In fact it is this electron "sea" that allows matter in the plasma state to conduct electricity.