The Sun is comprised of a state of matter that is rarely found on Earth. This state is known as plasma.

Molecules are particles made up of two or more atoms.

Solid, liquid and gas are the most common states of matter found naturally on Earth. Naturally occurring plasma is rare on Earth.

Melting is a physical process through which a solid is converted into a liquid. When a solid is heated, the distance between the particles increases, forces of attraction decreases. Eventually, the solid converts to liquid.

When a liquid is cooled down, the movement of molecules slows down.

Evporation is the physical process through which a liquid converts to a gas on absorbing heat. For example, liquid water from oceans, lakes, rivers and other water bodies, undergoes evaporation (changes into gas) by absorbing heat from the Sun.

The water vapour around us in the air cools down when it comes in contact with a cold object. Hence, droplets of water are seen on the surface of the glass.

Crystal is a solid and when a strong force is applied on it, it breaks into smaller pieces. This property of solids is known as brittleness.

An element is a substance which cannot be broken down into smaller units by any chemical reaction. Nitrogen is an example of element.

Water does not change colour as salt crystals are clear. We can see the salt particles in water at first, but when you stir they dissolve and the size becomes so small that it cannot be seen through the naked eyes.