Giving examples of solids, liquids, gases, and plasma is a common homework assignment in chemistry, physics, and physical science classes. Naming examples is a good way to start thinking about the properties of the states of matter.
Examples of Solids
A solid is a form of matter that has a defined shape and volume. Atoms and molecules in most solids are packed together more closely than in the other states of matter (with some exceptions). Unlike particles in other states of matter, atoms and molecules in a solid often assume regular arrangements (crystals). Examples of solids include:
- Iron bar
- Glass (no, it does not flow)
- Aluminum foil
Examples of Liquids
A liquid is a state of matter that has a defined volume, but can change shape. Liquids have the ability to flow and assume the shape of their container. This is because there is enough space between particles that they can slide past each other. Examples of liquids include:
- Mercury (a liquid metal)
Examples of Gases
A gas does not have a defined shape or volume, so it can expand to fill any size or shape of container. Particles in gases are widely separated, compared to those in liquids and solids. Examples of gases include:
- Natural gas
- Carbon dioxide
- Water vapor
- Natural gas
Examples of Plasma
Like a gas, plasma has no defined shape or volume. It can expand to fill a container. However, the particles in plasma are ionized (carry an electric charge) and very widely separated from each other. Examples of plasma include:
- Neon sign
- Earth’s ionosphere
- Sun’s corona
- Static electricity
- St. Elmo’s fire
- Rocket exhaust
Other States of Matter
While solids, liquids, gases, and plasma are the most familiar states of matter, scientists are aware of several others. These include:
- Liquid crystals: A liquid crystal is intermediate between a liquid and solid.
- Superfluid: A superfluid is like a liquid, but with zero viscosity.
- Bose-Einstein condensate: Bose-Einstein condensate is like a super-cold gas in which particles stop behaving independently of each other.
- Color-glass condensate: Color-glass condensate is a type of matter predicted to be found in atomic nuclei moving a near-light speed.
- Dark matter: Dark matter is a type of matter than neither absorbs nor emits light.
Transitions Between States of Matter
Changes in temperature and pressure cause matter to transition from one form to another. The most common phase transitions are:
- Freezing: Freezing is the transition from a liquid to a solid.
- Deposition: Deposition is the transition from a gas directly to a solid.
- Melting: Melting occurs when a solid changes into a liquid.
- Condensation: Condensation is when a gas transitions into a liquid.
- Sublimation: Sublimation is the change from a solid into a gas:
- Vaporization: Vaporization is the transition from a liquid into a gas.
- Recombination: Recombination or deionization is the change from a plasma into a gas.
- Ionization: Ionization is the phase change from a gas into plasma.