Unit 7 water and air

Water and air on Earth

ALL LIVING THINGSNEED

WATER

ANIMALS PLANTS

PEOPLE

WHAT’S WATER LIKE?

NO COLOUR

NO SMELL

NO TASTE

All living things need water and air to live.

• It is found in three STATES

Water changes state when you heat it or cool it.

SOLID LIQUID GAS

The three forms of water

• You can find water in 3 different forms:– Liquid– Solid– Gas

Water is a liquid.Ice is a solid at 0 degrees.

Water vapour is a gas at

a hundred degrees

DOES WATER CHANGE?

• Water turns to GAS when it is HOT.

• Water turns to SOLID when it is VERY COLD.

• Water turns to liquid at ROOM TEMPERATURE.

DOES WATER CHANGE?

It freezes

It melts It evaporates

It condenses

Water

• We need water for drinking.• We need water for swimming.• We need water for cooking.• We need water for cleaning.• We need water for washing.• We need water for watering the

plants.

USES OF WATER

SWIMMING WASHING

WATERING THE

PLANTS

DRINKING COOKING

CLEANING

USES OF WATER

WATER AND LAND• The Earth is covered with WATER and LAND.• There is more water than land on the Earth!• We can find water is many different places. Most

of the water is salty.

• We can find water in – A lake.– A river.– In a waterfall.– The clouds.– The seas.– Groundwater.– Reservoirs.– The icecaps.

Where we Where we find waterfind waterter

We find water in a lake. We find water in a

waterfall.

We find water in a river. We find water in the clouds.

We find water in the icecaps. We find water in the sea.

We find water in reservoirs.We find groundwater.

FRESHWATER

• Most of the water on Earth is –Saltwater.

• Only a little is –Freshwater.

FRESHWATER SALTWATER

Oceans and seas are saltwater.

Rivers, lakes, icecaps, groundwater and reservoirs are freshwater.

WATER HERE IS GAS.

WATER HERE IS LIQUID.

WATER HERE IS SOLID.

ALL ABOUT AIR

• Air is a mixture of gases.

• We cannot see air but it is all around us.

• People and animals breathe oxygen from the air.

• All living things need air to live.

• Plants can’t grow without air.

• People and animals can’t breathe without air.

Atmosphere is the layer of gases that sorround the Earth

AIR IS FOUND IN THE ATMOSPHERE.

Characteristics of air

• Air is a mixture of gases, but it consists mainly of OXYGEN and NITROGEN.

• As water it has NO SMELL, NO TASTE, AND NO COLOUR

OXYGEN

NITROGEN

WIND

• Wind is moving air.• Hot air goes up• Cold air goes down.• The difference in temperature causes

wind.• Wind moves air from one place to another.• This is why clouds move.

Types of wind• No wind• Little wind• Strong wind• Very strong wind

• Calm• Breeze• Gale• Hurricane

An anemometer measures how fast the wind is moving.

A weather vane tells us wind direction

Weather

• Weather is the state of the atmosphere at a certain time in certain places.

The weather can be windy.The weather can be sunny.

The weather can be cloudy.

The weather can be rainy.

The weather can be stormy. The weather can be snowy.

The weather can be foggy.

What’s the weather like today in Spain?

Temperatures and Precipitation

• When the weather is HOT, the temperature is HIGH.

• When the weather is COLD, the temperature is LOW.

PRECIPITATION

• Precipitation is water falling from the atmosphere to the ground.

• It can be:• LIQUID ---------RAIN DROPS• SOLID -------------- SNOW FLAKES• BALLS OF ICE --------- HAIL STONES

Measuring weather

• ANEMOMETER: WIND SPEED

• RAIN GAUGE: RAIN FALL

• TEMPERATURE: THERMOMETER.

FRESHWATER

• We can only drink CLEAN freshwater. We call this DRINKING WATER.

• Water from rivers and lakes is NON-DRINKING WATER.

DON’T WASTE WATER

• We must save water. • Only the 3% of all the water on Earth is

freshwater.

The drought

• When it doesn´t rain for a long time it’s difficult for the plants and fish to survive.

• They usually happen in summer.

WATER CYCLE

What is the water cycle?

• The water cycle is a continuous process of EVAPORATION, CONDENSATION, PRECIPITATION and COLLECTION

The water cycle• When it is hot Water from the sea evaporates.• The water vapour condenses into tiny drops and

form clouds.• When the clouds are cold, it rains or snow.• The rain or snow falls into the sea.

Evaporation

When the water turns into a gas

Condensation

Precipitation

COLLECTION

Water on Earth is always changing state and place. The water cycle.

EVAPORATION

• When the Sun heats water, water vapour rises.

CONDENSATION

• When the water vapor cools, it turns into water drops and form clouds.

PRECIPITATION

• The wind moves the clouds. When the clouds cool, water from the clouds falls as rain. If it is very cold, the water freezes and falls as snow. Rain and snow are both types of precipitation.

COLLECTION• The water that falls to the ground eventually

goes into rivers. It can travel to the rivers across the surface of the Earth or underground. Rivers take the water back to the ocean and seas.

•Now the cycle begins again.