Most substances can exist as a solid, liquid or gas. They can change state, usually when they are heated or cooled. For example, liquid water turns into water vapour when it is heated enough ...

Although the three states of matter are solid, liquid, and gas, not all substances seem to fit perfectly into one of these groups. Take a look at the substance below and see if you can decide whether ...

Well-designed and operated wastewater facilities can unlock valuable resource recovery—reclaiming water, energy, and ...

Even when liquids change their shape, they always take up the same amount of space. Their volume stays the same. Examples of gases include steam, helium and oxygen. They are often invisible.

Students explore the attractions and motion of atoms and molecules as they experiment with and observe the heating and cooling of a solid, liquid, and gas.