Science
What is A colloid?
A colloid is a mixture in which tiny particles of one substance are spread evenly through another but never settle out. Milk, fog, jelly, and whipped cream are colloids — their particles are bigger than a solution's molecules, yet too small to sink.
See it, don’t just read it.
Watch a 2-minute lesson with voice + animation that explains a colloid.
Key things to understand
- 1Particles are spread through a medium but don't dissolve or settle.
- 2They're larger than dissolved molecules but too small to filter out easily.
- 3Examples: milk (fat in water), fog (water in air), jelly, paint.
- 4Colloid particles scatter light (the Tyndall effect), so the mix looks cloudy.
- 5Constant random jostling keeps the particles suspended.
Frequently asked questions
- How is a colloid different from a solution?
- In a solution, particles dissolve completely and are invisible; in a colloid, larger particles stay suspended and scatter light, making it cloudy.
- What is the Tyndall effect?
- The scattering of a light beam by colloid particles — why you can see a flashlight's beam in fog or milk.
- Why don't colloid particles settle?
- They're so small that constant molecular bombardment keeps them jostling and suspended instead of sinking.