The molecules of a gas move apart when they collide. The average kinetic energy of the particles in a liquid (or solid) is small enough that the forces of attraction between them is sufficient to hold the particles close together. The molecules in a liquid (or solid) do not move apart.

When a gas changes into a liquid, it is called condensation. When a gas changes into a solid, it is called deposition . When a liquid changes into gas, it is called evaporation. Phase changes are usually caused by changes in temperature or pressure.

All gases share common physical properties. Like liquids, gases freely flow to fill the container they are in. But while liquids have a defined volume, gases have neither a defined volume nor shape. And unlike liquids and solids, gases are highly compressible.

Key Takeaways: Examples of Solids, Liquids, and Gases

• The three main states of matter are solid, liquid, and gas. Plasma is the fourth state of matter.
• A solid has a defined shape and volume. A common example is ice.
• A liquid has a defined volume, but can change state.
• A gas has neither a defined shape nor volume.

Examples of Solids

• Brick.
• Coin.
• Iron bar.
• Banana.
• Rock.
• Sand.
• Glass (no, it does not flow)
• Aluminum foil.

Examples of Gas to Liquid (Condensation) Water vapor to dew – Water vapor turns from a gas into a liquid, such as dew on the morning grass. Water vapor to liquid water – Water vapor forms water droplets on the glass of a cold beverage.

Examples of Gases

• Hydrogen.
• Nitrogen.
• Oxygen.
• Carbon Dioxide.
• Carbon Monoxide.
• Water Vapour.
• Helium.
• Neon.

Any gas can be converted to a liquid by lowering the temperature and increasing the pressure. The pressure and temperature are dependent on the particular gas. This kind of phase change–liquid to gas–is called evaporation or vaporization. Water vapor can in turn be cooled to form liquid water.

Boiling and Condensation Again, at a certain temperature called the boiling point, the molecules will gain enough energy to break free and become a gas. The boiling point for water is 100 degrees C (212 degrees F). When the opposite occurs and a gas becomes a liquid, it is called condensation.

Freezing, or solidification, is a phase transition in which a liquid turns into a solid when its temperature is lowered to or below its freezing point. Most liquids freeze by crystallization, the formation of a crystalline solid from the uniform liquid.

Sublimation (noun, “SUB-lim-A-shun”) This is the process in which a substance goes directly from a solid state to a gas, without passing through the liquid phase.

Condensation

When thermal energy is added to a substance, its temperature increases, which can change its state from solid to liquid (melting), liquid to gas (vaporization), or solid to gas (sublimation).

Matter can change from one state to another if heated or cooled. If ice (a solid) is heated it changes to water (a liquid). This change is called MELTING.