KS3 Science · Chemistry
Particles and states of matter
Seven short lessons. Look at the picture, learn three things, then play.
Test yourself
Puzzles
These two are for the whole topic. Each lesson has a word search and a crossword of its own as well, at the top of its page.
Knowledge organiser
The whole topic on one page. Tap it to make it bigger.
Take it with you
Save these to print or read later.
Key words
Particle A tiny piece of matter, far too small to see
Particle model The idea that everything is made of tiny moving particles
Solid Has a fixed shape and a fixed volume
Liquid Flows and takes the shape of its container, but has a fixed volume
Gas Spreads out to fill its container, and can be squashed
Melting Changing from a solid to a liquid
Freezing Changing from a liquid to a solid
Evaporating A liquid turning into a gas at its surface, at any temperature
Boiling A liquid turning into a gas all through the liquid
Condensing Changing from a gas to a liquid
Subliming Changing from a solid straight to a gas
Melting point The temperature at which a solid melts
Boiling point The temperature at which a liquid boils
Gas pressure Caused by gas particles hitting the walls of their container
Diffusion Particles spreading out from where there are many to where there are few
Brownian motion The random jiggling of a tiny speck as particles hit it
Density The mass of one cubic centimetre of a substance
Vacuum A space with no particles in it