The Particle Model

What is a particle?

particles are small pieces of matter that make up everything

state of matter - solid

particles remain in a fixed shape, arranged in orderly rows and columns, particles vibrate in a fixed place, particles touching

states of matter - liquid

particles are arranged randomly, all touching, take the shape of the container, particles can flow

state of matter - gas

particles are arranged randomly, they are not touching, move freely, can be compressed

properties of a solid

fixed shape, cannot be compressed, high density

properties of a liquid

fixed volume, takes the shape of the container, flows easily

properties of a gas

flow, fill their container, no fixed shape/volume, can be compressed, low density

what is diffusion

diffusion is the movement of particles from an area of high concentration to an area of low concentration

why does diffusion happen?

diffusion occurs in gases and liquids as the particles are moving randomly and colliding witht he walls of their container, eventually, the new particles change direction/move enough times to spread through the whole liquid/container

example of diffusion

perfume particles spreading the scent through the room

what factors affect diffusion?

• temperature

• the difference between how many new particles vs old particles there are

what is brownian motion?

the seemingly random movement of particles suspended in fluids

why does brownian motion happen?

In a liquid, the particles are constantly moving, meaning that they bombard the particle suspended in the fluid from many different angles, causing it to move around in a ‘random’ way

what is gas pressure?

Gas pressure is the force exerted by gas particles colliding with the walls of their container.

why does gas pressure happen?

When particles collide with their container, they exert force. when the temperature inside the container rises, the particles gain more kinetic energy, meaning they move faster, increasing gas pressure.

example of gas pressure

car tyres being heated up to increase gas pressure

what is a vacuum

a vacuum is a container with no particles inside it whatsoever.