Page 208 - Primary Five Science

Cohesion and adhesion forces

Cohesion is the force of attraction between molecules of the

same substances. E.g. water and water, wood and wood.

Adhesion is the force of attraction between molecules of differ-

ent substances e.g. water and glass

Changes of states of matter

Matter can change from one state to another. In most cases,

temperature has something to do with the changes.

Some substances can easily change from one state to another

A substance is a material that is made up of only one kind of

matter

Solids, liquids and gases are called the three states of matter.

Materials can be changed from one state to another by heating
or cooling.

Water can be observed as a liquid, a solid (ice), or a gas (water
vapour) and moves around the environment in a process

known as the water cycle.