Diffusion

ALL substances are made of particles.

Particles are too small to see without microscopes.

Probes have been developed that can sense forces between particles.

• Diffusion - The movement of particles in a gas or liquid from high to low concentration.

• Molecules diffuse DOWN the concentration gradient. They become LESS concentrated.

• High concentration is when there are a lot of the same particles near eachother, and low concentration is when they are more spread out.

• When you can smell food coming from the kitchen, the particles are diffusing through the air from the kitchen and reaching where you are.

• The particles do not consciously move to a lower concentration, this is the average movement over time. Particles move randomly.

• Eventually, the particles will spread evenly through their container.