A colloid is a mixture in which one substance of microscopically dispersed insoluble particles are suspended throughout another substance. However, some definitions specify that the particles must be dispersed in a liquid, and others extend the definition to include substances like aerosols and gels.
The types of colloids includes sol, emulsion, foam, and aerosol.
- Sol is a colloidal suspension with solid particles in a liquid.
- Emulsion is between two liquids.
- Foam is formed when many gas particles are trapped in a liquid or solid.
- Aerosol contains small particles of liquid or solid dispersed in a gas.