Chapter 7

This chapter is mostly about solid, liquid and gas, which have been learnt before.

Substance exists in 3 states:

Solid: - has fixed shape and volume
- has high density
- cannot be compress

Liquid: - has fixed volume but no fixed shaped
- has high density
- cannot be compressed

Gas: - no fixed shape or volume
- has low density
- can be compressed

I also learn about the movement and arrangement of the particles in solid, liquid and gas.

The only difference is that I learn about:

Brownian motion: - Observed in liquid or gases.
- The random or irregular motion of smoke particles in air.