Download The Water Cycle - Science Department

Learning Objectives:

To be able to identify the steps in the water
cycles
Keywords: water cycle, cooling, clouds,
transpiration, percolation, precipitation,
condensation, water vapor, evaporation, ocean,
surface run-off
 There
are 3 cycles of matter
called the biogeochemical cycles.
 These
include:
1. The water cycle
2. The carbon cycle
3. The nitrogen cycle


The water cycle describes how water moves on,
above, or just below the surface of our planet.
Water molecules move between various locations
- such as rivers, oceans and the atmosphere - by
specific processes. Water can change state.
1.Water Cycle
2.Condensation
The movement of water between the atmosphere and Earth. It
includes: Evaporation, Condensation, Precipitation, Surface
Runoff, Transpiration and Perspiration.
The process where water vapor changes from a gas to liquid
water.
3.Transpiration
When plants release water through pores in their leaves back
into the atmosphere.
4.Percolation
Water filtering down through the soil due to gravity
5.Cloud
Millions of tiny water droplets or crystals. They form when
water vapor in the air condenses to form liquid water or ice
crystals. They can only form when dust particles and cool air
are present**
6.Evaporation
The process where liquid water changes to a gas as water
vapor.
7.Surface
Runoff
Water that cannot be absorbed into the surface (the ground is
too dense) but runs along it.
8.Water Vapor
When water is in the gas state.
9.Precipitation
Any form of water that falls from clouds and reaches Earth's
surface. Rain, snow, or hail
1) Evaporation
 Energy from the Sun heats the Earth’s
surface and water evaporates from
oceans, rivers and lakes. The warm air
rises, carrying water vapor with it.
2) Transpiration
 Transpiration from plants releases water
vapor into the air.
3) Condensation
 The moist air cools down as it rises. Water
vapor condenses back into liquid water,
and this condensation process produces
clouds.
4) Precipitation
 As the water droplets in the cloud get
bigger and heavier, they begin to fall as
rain, snow and sleet. This is
called precipitation
Learning Objectives:

To be able to identify the steps in the carbon
cycle
Keywords: carbon cycle, respiration,
combustion, photosynthesis, fossil fuel

Carbon cycle: the process by which carbon moves from
the atmosphere into the Earth and its organisms and
then back again.

Respiration: the process by which cells use oxygen to
break down carbohydrates and obtain energy

Combustion: the process of burning something.


Photosynthesis: the process in which green plants use
energy from the sun to transform water and carbon
dioxide into oxygen and carbohydrates.
Fossil fuel: a natural fuel such as oil, coal or gas,
formed in the past from dead organisms.



Carbon is passed from the atmosphere, as
carbon dioxide, to living things.
It is then passed from one organism to the
next in complex molecules, and returned
to the atmosphere as carbon dioxide
again.
This is known as the carbon cycle.
1)
Removing carbon dioxide from the
atmosphere
Plants use carbon dioxide from the atmosphere
for photosynthesis. The carbon becomes part
of complex molecules in the plants, such as
proteins, fats and carbohydrates.
2) Passing carbon from one organism to the next
When an animal eats a plant, carbon from the plant
becomes part of the fats and proteins in the
animal.
3) Returning carbon dioxide to the atmosphere
Carbon dioxide is released to the atmosphere
through respiration by animals, plants and
microorganisms. It is also released by
the combustion of wood and fossil fuels (such
as coal, oil and natural gas).
4) Decomposition or decay also releases carbon
dioxide. This process happens faster in warm,
moist conditions with plenty of oxygen because
it involves microorganisms.
Learning Objectives:

To be able to identify the steps in the
nitrogen cycle
Keywords: nitrogen cycle, nitrogen fixation,
denitrification



Nitrogen cycle: processes by which nitrogen
passes from air to soil to organisms and back
to air or soil.
Nitrogen fixation: the conversion of
nitrogen in the atmosphere into a form that
plants can use
Denitrification: the conversion of nitrates in
soil into nitrogen gas that goes into the
atmosphere



Nitrogen compounds found in cells
include proteins.
Nitrogen from the air is converted into a
form that plant roots can absorb. It forms part
of nitrogen compounds in the plants, and is
then passed from one organism to the next.
It is returned to the atmosphere as nitrogen
gas. This is the nitrogen cycle.



About 78% of the air is nitrogen gas.
But plants can not use it to make proteins
straight from the air.
It must be converted into a nitrates which is a
combination of nitrogen and oxygen.


Nitrogen-fixing bacteria in the roots of plants
are able to do this.
Lightning can also convert nitrogen gas into
nitrates.

Plants absorb nitrates from the soil and use
these to make proteins.


When an animal eats a plant, nitrogen from
the plant’s proteins becomes proteins in the
animal.
Nitrogen is also passed from one animal to
another by feeding.


Decomposers break down urea (urine), faeces
(poop) and dead bodies.
This results in nitrogen being returned to the
soil, which the bacteria can convert into
nitrates for plants to absorb.

Denitrifying bacteria in the soil break down
nitrates and return nitrogen gas to the air.