The Water CycleUnit 9 – Day 1

Please open your red textbook to page 4.

Ann Morris, Science Advisory Teacher, PPEC, Neyland. 20.4.02The continuous movement of water from the ocean to the atmosphere to the land and back to the ocean

Did you know that …

• there is the same amount of water in the world now as there was hundreds of millions of years ago?

So …..

• Where does it come from?• And where does it go?

Evaporation• Water in the sea,

lakes, rivers, streams, ponds and puddles is heated by the sun.

Evaporation• The heated water

evaporates to become water vapour. This is light, and floats up into the air – like the steam from a hot cup of tea.

Water from the oceans and the Earth’s surface change into water vapor. Energy from the sun causes evaporation.

Transpiration

• The process of giving off water vapor containing water and waste products through leaves and skin.

Plants absorb soilwater through their roots and this water can originate from deep in the soil. Transpiration accounts for approximately 10% of all evaporating water.

Condensation• As the water

vapour rises into the air, it gradually cools and condenses to form minute droplets of water.

• These billions of tiny droplets gather together to form clouds.

Water vapor cools and changes into water droplets that form clouds in the atmosphere.

Rain

When these droplets become too heavy, they fall as rain.

Precipitation:Rain, snow, sleet, or hail that falls from the clouds onto the Earth’s land and oceans.

Back to the sea• The rainwater

flows into streams and rivers and into underground stores.

• Eventually, the rivers reach the sea and the cycle starts all over again.

evaporation

condensation

Percolation: Downward movement of water through pores and other spaces in soil due to gravity.

Click the cloud to watch the water cycle in action!

http://teacher.scholastic.com/activities/studyjams/water_cycle/

Can you fill in the missing words?

When water in the sea is heated by the sun it

and changes into

This is light, and floats up into the air like

from a hot cup of tea.steam evaporate

swater vapour

As the

rises into the air it gradually cools and

to form tiny droplets of water.

These join together to make

condenses water vaporclouds

When the droplets become too heavy, they fall as

The rain flows into streams and rivers, and eventually the rivers reach the

Now, the cycle

WATER CYCLEDay 2

Runoff

Water that flows over the ground surface rather than soaking into the ground.

Runoff is the movement of landwater to the oceans, chiefly in the form of rivers, lakes, and streams. Runoff consists of precipitation that neither evaporates, transpires nor penetrates the surface to become groundwater. Even the smallest streams are connected to larger rivers that carry billions of gallons of water into oceans worldwide. Excess runoff can lead to flooding, which occurs when there is too much precipitation.

+ Water Table?

=

The upper surface of underground water; the upper boundary of the zone of saturation

Groundwater is all the water that has penetrated the earth's surface and is found in one of two soil layers.

As the amount of groundwater water increases or decreases, the water table rises or falls accordingly.

Properties of Water!

Boiling Point: 100o C or 212o F

Melting Point: 0o C or 32o F

Density: 1 g/ml

BUT…. What is density?