A mixture is something that contains two or more substances.
Mixtures can be heterogeneous or homogeneous.


In a heterogeneous mixture, we can see the individual substances.
The individual substances can be separated easily.

A fruit salad is a heterogeneous mixture.


In a homogeneous mixture, it isn’t possible to see the different substances.

Mayonnaise is a homogeneous mixture. It contains oil, eggs and vinegar, but we can’t see these individual ingredients.

Salt water in the sea is a homogeneous mixture.
It is a mixture of water, salt and other minerals.

Air is a homogeneous mixture.
It is a mixture of:
21% oxygen,
78% nitrogen,
and approximately 1% other trace gases, primarily argon.