Unit 3 - water

Unit 3WATER

1- Water- On Earth: 71% of the Earth’s surface is covered by water (salt water is 97%, fresh water just 3%).

Water states

Seawater and continental waters

What are rivers?A river is a large natural stream of water emptying into an ocean, lake,

or other body of water and usually fed along its course by converging tributaries.

Parts of a river:-River source-Tributaries-Basin-Flow (depends on the

season)

The world’s most important rivers

ActivitiesExercises 1 and 2 on page 40.

2- The course and flow of a riverThere are three stages in the course of a river:

Lower course of a river

The flow of a riverThe quantity of water in a river is called the flow.The more precipitation there is,the greater the flow will be.

The importance of rivers-Transport-Water supply: Canals, reservoirs-Electricity: dams, power stations

ActivitiesExercises 1 to 3 on page 43.Exercise 3 on page 48.

3- Lakes, groundwater and glaciers

Different terms:-Lake-Lagoon (small)-Inland sea (salt water)

Different origins:-Precipitation-Rivers or groundwater-Glaciers

What are lakes?

Where are groundwater and glaciers found?GROUNDWATER. Aquifers.

The importance of groundwater

-Drinking water-Source for rivers and lakes-To grow plants

Glaciers

Icebergs

HomeworkActivities 2-3 on page 45.

4- Oceans and seas

They hold almost all the world’s liquid water, that is salt water.Salinity is different depending on if the sea is warmer or colder.Warm = + saltCold = - salt

What are currents, tides and waves?Map of ocean currents

Ocean currents

Tides

Waves

The importance of oceans and seas

-Food-Raw materials-Energy-Tourism-Transport

ActivitiesExercises 1, 2 (a, b) and 3 on page 46-47.

What problems are related to water today?

WATER CONSUMPTION AND DISTRIBUTION-3% Fresh water -> 0,014% available-Increase in population -> increase in consumption-Bad distribution-Consequences: droughts or floods

Water pollution and acid rain

Work at homeExercises 1, 2, 5 and 8 on pages 48-49.

PractiseGo to page 50, put all your attention in understanding the map, and then, make exercises 1 to 3 in your notebook.

Practise IIGo to page 51, put all your attention in understanding the text, and then, make exercises 1 to 3 in your notebook.