1. The Carbon Cycle
By Moira Whitehouse
PhD

2. •Carbon is an element found throughout the
universe.
• It is found in all living things and without
carbon there would be no life on Earth.
• The characteristics of the remarkable
carbon atom make possible the compounds
that are necessary for life on Earth.

3. • Carbon is also part of nonliving things
such the oceans, rocks ,animal shells,
and the atmosphere.
• Carbon doesn’t just stay in one place
however. It’s always on the move.
• Carbon atoms continually move
through living things, the oceans, the
atmosphere and the crust of the
Earth.
• This movement is known as the
carbon cycle

4. Carbon dioxide, a gas in our atmosphere,
is partly carbon and is an important part
of the carbon cycle.
A carbon dioxide molecule is made up of
one part carbon and two parts oxygen.
carbon
oxygen

5. Carbon moves through its “cycle” in several ways,
one way is by photosynthesis.
During
photosynthesis,
carbon dioxide is
taken into the
plant and changed
into plant food.
The carbon is then
stored in this
food. In this
process of
http://cfs.nrcan.gc.ca photosynthesis,
oxygen is given

6. Carbon on the move through respiration
(breathing)
During
respiration,
animals take
in oxygen
and breathe
out carbon
dioxide.

7. In this
diagram we
see the
exchange of
the gases—
carbon
dioxide and
oxygen
between
plants and
animals.
arthursclipart.org

8. Here we see carbon on the move through the
food chain.
Plants are the foundation of a food chain. The
carbon that is stored in its food is passed down
from one animal to another though this chain.

9. And here, carbon is being moved through
decomposition.
That’s because when plants and animals die, their
bodies decay and carbon dioxide is released into
the air—carbon moves back into the air.

10. Let’s review what we have studied so far.

11. Diagrams in the
next four slides
show how
carbon moves in
its cycle.
1. Carbon
dioxide in the
air moves to
plants through
photosynthesis

12. 2. Carbon
moves from
plants to
animals
through the
food chain

13. 3. From live
plants and
animals
(respiration)
and burning
fuel back into
the atmosphere
as carbon
dioxide.

14. 4. From dead
plants and
animals
through
decomposition
back into the
atmosphere as
carbon dioxide.

15. Here is a website with three
choices which show the movement
of carbon through the carbon
cycle. Simply choose download
and then select the process you
wish to study.
http://www.kscience.co.uk/animations/carbon
_cycle.htm

16. Now let’s look at how fossil fuels fit
into the carbon cycle.
Remember fossil fuels are our main
source of energy.
We use fossil fuels to:

17. 1. Power all our vehicles--
cars, trucks, buses, trains, planes and
tractors.

18. 2. Generate our electricity.
Steam
Often, coal or natural gas is burned to heat
water. The water changes into steam which
turns a turbine which then turns a coil of wire
inside a magnet generating electricity.

19. Large generators produce the electricity we use
in our homes, schools and work places.

20. 3. Power all the factories that make the
things we use.

21. Do you remember how fossil fuels—crude
oil, coal and natural gas—are formed?
Yes, they are formed from the remains of
plants and animals.
The carbon from the dead plants and
animals is stored in fossil fuel.

22. However, in order to use fossil fuels for
energy, we must burn them.
And when they burn, carbon dioxide is
given off and returned to the air—
carbon on the move again.

24. Some of this
carbon is
cycled back
through
carbon
dioxide to
the plants
particularly
trees.

25. Can you
follow
carbon
moving
through
the cycle
in the
diagram
on the
left.
National Center for Atmospheric Research and UCAR

26. The Carbon Cycle