Chemistry

Free online chemistry lesson for elementary school, middle school and high school.

 

Sates of matter

States of matter and their changes

The three states of matter

We distinguish for water and other substances three different states: Solid, liquid and gaseous states.
- In the solid state there are glaciers, sea ices, hail and snow ( composed of tiny ice crystals ).
- In the liquid state there are rivers, seas, oceans, rain,  and also clouds and fogs (composed of tiny water droplets ).
- In the gaseous state there is water vapor always invisible to the naked eye.

Changes of states


Water can change its state if temperature varies and under the action of Sun and wind.

Definitions:
- Melting (or fusion): transition from solid to liquid state.
- Vaporization: transition from liquid to gaseous state.
- Liquefaction (or condensation): transition from gaseous to liquid state.
- Solidification ( or freezing ): transition from liquid to solid state.
- Sublimation: transition from solid to gaseous state.
- Deposition: transition from gaseous to solid state.

Comments:
The vaporization of a liquid may be gradual and natural (such as when exposed to sunlight ). We then say that there is " evaporation ". It can also be obtained by a rapid temperature rise which causes the formation of gas bubbles: this is called " boiling ".

- Sates of matter: The three states and their properties at molecular scale ( with animations to explain the molecules move in solids, liquids and gases )

- Solids and liquids: A game which purpose is to shows differences between solid state and liquid state.

- Changing states: a flash game about changes of state

- States of water worksheet: A worksheet for kids where blank must be filled with changes of state ( evaporates, freeze, boils ...)

- Change of state worsheet: a three pages worksheet about three states, changes of states, energy and molecules.

- States of matter activities: a pdf document that provide various activities like card game about solids, liquids and gases, or a game board.

- Changing states game: a flash game in arctic about water and changes of state.

- States of matter experiment: Various experiments explained with videos

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