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Unit 6 Water
Surface Water
Glaciers are areas of moving ice. They are found at high altitudes. Most of the world's fresh water is found in the snow and ice of glaciers.
A river is a flow of water that is bigger and deeper than a stream. Rivers flow into lakes and oceans.
A stream is a very small river that originates in mountains.
A lake is a large area of water surrounded by land. Most lakes on the Earth contain fresh water.
An ocean is a huge area of salt water. There is only one ocean called the World Ocean. It consists of five separate parts:
The Pacific
The Atlantic
The Indian
The Southern
The Arctic
Ground Water
Most groundwater comes from rain. Groundwater goes very slowly from high places like mountains and hills to low places like plains and valleys.
A spring is a place where groundwater meets the Earth's surface.Streams, rivers and lakes originate in springs.
We find groundwater in layers of sandstone called aquifiers.
Below an aquifier there is a layer of clay that traps groundwater.
To get water out of the aquifies we drill wells and pump the water out.
The Three States of Water
Water exists in three states: Solid like ice, Liquid like tap water, gaseous like gas.
When water flows it is a liquid. Rain, rivers and oceans are examples of this.
Gaseous water is hard to see. Clouds, steam, fog and mist are examples of this.
Changes in the states of water
Condensation is when water vapour cools and becomes water. It goes from a gaseous state to a liquid state.
Evaporation is when water boils and becomes a gas. It goes from a liquid state to a gaseous state.
Freezing is when liquid water cools and becomes a solid like ice.
Melting is when solid water heats and becomes a liquid.
Sublimation is when solid water becomes gaseous like ice crystals on frozen food.
Deposition is when gaseous water becomes solid water.
The Water Cycle
*** Please refer to 2º primaria science unit 7 for the water cycle. ***
