The Water Cycle
Unit 9 – Day 1
Please open your red textbook to page 4.
The continuous movement of water from the ocean
to the atmosphere to the land and back to the ocean
Ann Morris, Science Advisory Teacher, PPEC, Neyland. 20.4.02
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.
Percolation: Downward
movement of water through
pores and other spaces in soil
due to gravity.
condensation
evaporation
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
evaporates
water vapour
As the
rises into the air it
gradually cools and
to form tiny droplets of
water.
These join together to
make
clouds
condenses
water vapor
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 CYCLE
Day 2
Runoff
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 that flows
over the ground
surface rather
than soaking into
the ground.
+
=
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?