1. Year 7 REVISION – Particle Theory
Brownian Motion: the random movement
of microscopic particles in a fluid, as other particles randomly bump them.
Solids, liquids and gases
are all made up of
PARTICLES. In a
solid PARTICLES are held very CLOSE together to form a REGULAR pattern, where they can only VIBRATE. In liquids
they are CLOSE together, but they can SLIDE past each other and they have no REGULAR pattern. In gases, PARTICLES Are free to MOVE in all DIRECTIONS at a very high speed.
States of Matter
KEYWORDS
Particle
A tiny portion of a substance
Volume
The amount of space taken up by a substance
Density
Heaviness for its size
Compress
Making a volume smaller by increasing the pressure
Diffusion
Random mixing of particles
Vibration
Movement of a particle around a fixed position.
Gas pressure
The force of collisions of particles from a gas on a container.
Melting point
The exact temperature at which a substance melts
Boiling point
The exact temperature at which a substance boils
Evaporation
When a substance turns from a liquid to a gas
Condensation
When a gas cools and turns into a liquid 1 2 3 4
Solid to liquid= MELTING
Liquid to gas= EVAPORATION
Liquid to solid= FREEZING
Gas to liquid= CONDENSATION
Extension:Some substances can turn from a solid to a gas. This is called SUBLIMATION. An example of this substance is dry ice.