Facts At Your Fingertips: Matter and materials – States of matter

Pocket Genius Science: Matter and materials – States of matter

Matter is everywhere, but you cannot always see it. There are four main types, or states, of matter—solid, liquid, gas, and plasma.

Each state is made up of moving particles, but they look and behave very differently.


In solids, the particles are packed together so tightly that they vibrate rather than move around. Solids can be hard or soft, huge or tiny, and everything in between, but they always have a fixed shape and volume and occupy a definite space.


The particles in a liquid are also close, but they are not held together as strongly as in a solid, so they can move around. This means a liquid has no fixed shape and usually takes on the shape of whatever container it is in. A liquid has a fixed volume, but it varies in thickness, or viscosity, which affects how freely it can flow.


The particles in a gas are far apart and can move freely, so gases have no fixed shape or volume. Gases can be compressed (squeezed so the space between the particles decreases) or expanded (the space increases) to fit a container. Most gases are invisible.


Plasma is rarely seen on Earth, but it is found throughout the universe. Like a gas, it has no fixed shape or volume. However, it contains electrically charged particles and exists only under certain conditions, such as in places with high temperatures or radiation. Streams of plasma can be seen in this plasma lamp.