PowerPoint Presentation made by the Romanian student Antonela Pavel on ways of saving energy.

1. By:Antonela Pavel
7th grade
Scoala Gimnaziala Magura

2. What is energy?
• Energy is the ability to do work. Taking
your dog for a walk, eating, playing and
doing your homework are way to use
energy.

3. • Energy is an indirectly observed
quantity that is often understood as
the ability of a physical system to do
work on other physical systems.
However, this must be understood as
an overly simplified definition, as the
laws of thermodynamics
demonstrate that not all energy can
perform work.

4. History
• The word energy derives from the Greek
ἐνέργεια, which possibly appears for the first
time in the work of Aristotle in the 4th century
BCE.
• The concept of energy emerged out of the
idea of vis viva (living force), which Gottfried
Leibniz defined as the product of the mass of
an object and its velocity squared; he believed
that total vis viva was conserved.

5. • In 1807, Thomas Young was possibly the
first to use the term "energy" instead of
vis viva, in its modern sense. Gustave-
Gaspard Coriolis described "kinetic
energy" in 1829 in its modern sense, and
in 1853, William Rankine coined the term
"potential energy".

6. Units of energy
We can measure energy in different units:
In Joules(J).
In kilojoules(kJ),that are used to express larger
quantities of energy(1000 J=1kJ).
In calories(cal), that often measures heat energy.
In kilocalories(kcal), that are used to express larger
quantities of heat.
 Calories and Joules measure different units of
energy: 1cal=4.18J

7. Types of primary Energy
 Wind Energy
 Hydroelectric
 Solar Energy
 Geothermal Energy
 Nuclear Energy

8. 1. Wind energy
• Wind power is the
conversion of wind
energy into a useful form
of energy, such as using:
wind turbines to make
electrical power,
windmills for mechanical
power, wind pumps for
water pumping or
drainage, or sails to
propel ships.

9. Wind energy
Advantages:
It’s unlimited and non-polluting.
The cost of building and maintaining a wind
farm is low.
Disadvantages:
It’s a variable source of energy.
Wind turbines are hazard for birds.
Wind turbines produce noise pollutions.

10. 2. Hydroelectric
1. Hydropower or water power is
power derived from the energy
of falling water, which may be
harnessed for useful purposes.
2. History: Early uses of
waterpower date back to
Mesopotamia and ancient Egypt,
where irrigation has been used
since the 7th millennium BC and
water clocks had been used since
the early 2nd millennium BC.

11. 3. Solar energy
• Solar energy can be captured by ray panels
connected to the systems which warm water
or produce electricity.

12. • Solar energy, radiant light and heat from
the sun, has been harnessed by humans
since ancient times using a range of ever-evolving
technologies. Solar energy
technologies include solar heating, solar
photovoltaics, solar thermal electricity
and solar architecture, which can make
considerable contributions to solving
some of the most urgent problems the
world now faces.

13. Solar Energy
Advantages:
It’s clean.
Big power stations are not needed.
It’s unlimited
Disadvantages:
It’s a variable source of energy.
Solar panels are expensive.

14. 4. Geothermal energy
• It uses the temperature of the water under
the ground, that is pumped to the surface to
heat homes or greenhouses or to produce
electricity.

15. • Geothermal energy is thermal energy
generated and stored in the Earth. Thermal
energy is the energy that determines the
temperature of matter. The Geothermal
energy of the Earth's crust originates from the
original formation of the planet (20%) and
from radioactive decay of minerals (80%).The
geothermal gradient, which is the difference
in temperature between the core of the
planet and its surface, drives a continuous
conduction of thermal energy in the form of
heat from the core to the surface.

16. 5. Nuclear energy
• Nuclear energy is the energy released by
reactions involving the nuclei of atoms. We
transform nuclear energy into electricity in
nuclear power stations.

17. Types of secondary energy
 Electrical Energy
 Thermal Energy
 Light Energy
 Sound Energy
 Chemical Energy

18. 1. Electricity
• Electric potential energy,
or electrostatic potential
energy, is a potential
energy (measured in
joules) that results from
conservative Coulomb
forces and is associated
with the configuration of a
particular set of point
charges with in a defined
system.

19. 2. Thermal energy
• Thermal energy is the part of the
total internal energy of a
thermodynamic system or
sample of matter that results in
the system temperature. This
quantity may be difficult to
determine or even meaningless
unless the system has attained its
temperature only through
cooling, and not been subjected
to work input or output, or any
other energy-changing
processes.

20. 3. Light energy
• Solar energy, radiant
light and heat from the
sun, has been harnessed
by humans since ancient
times using a range of
ever-evolving
technologies. Solar
energy technologies
include solar heating
and solar photovoltaics.

21. 5. Sound energy
• Sound energy is associated with wave
transmited by the air and produced by
vibrations objects. We can say that sound
energy is a form of mechanical energy.

22. 6. Chemical energy
• Chemical energy is the part of energy in a
substance that can be released by a chemical
reaction. It’s stored in substances and it can
be absorved during chemical processes.

23. We can save energy!!!
1.Do you have a shower?
If you have a shower: You’re clean and green. You
know that it’s important to save water!
If you don’t have a shower: Baths use a lot more
water than showers. Take showers, not baths and
you’ll save enough water each week for 1000 cups of
tea!

24. 2.Is the tap running when you clean your
teeth?
• YES??? Did you know that 10-14 litres of water
comes out every minute? If you switch the tap
off you can save a lot of water.
• NO??? You are saving a lot of water 10-14
litres of water comes out every minute!

25. 3.Do you turn off the monitor when
you’re not using the computer?
• YES??? It saves energy, and it also means the
monitor will last longer.
• NO??? Screen-savers don’t save much energy.
You should switch your monitor off if you are
not using it.

26. 4.Do you write on both sides of a piece of
paper?
• YES??? It’s clear that you love trees! Make
sure that you only print things when you really
need to. You can buy recycled paper too.
• NO??? Cutting down trees is a real problem
for the environment. Remember not to waste
paper!

27. 5.Are more than 2 electrical things on
your room at the same?
• YES??? If you are using lots of electrical things,
then you are using lots of energy. Make sure
you switch things off if you don’t need them-you’ll
help you parents save money too.
• NO??? You are really thinking about how
much energy you use.

28. 6.Is your TV on standby when you’re not
watching it?
• YES??? When TVs are on standby they are still
using energy. You should switch all electrical
things off.
• NO??? You know that electrical things still use
energy when they are on standby.

29. 7.Do you turn off the lights when you
leave a room?
• YES??? Make sure you use energy saving light
bulbs too, and you will save more energy.
• NO??? You are wasting energy if you leave the
lights on in the house. Remember to switch
them off when you leave a room.

30. 8.Do you open the window when the
heater or air-conditioner is on ?
• YES??? If you open a window, switch off the
heater or air-conditioner or you are wasting
energy.
• NO??? You know that it doesn’t make any
sense to open a window when the heater or
air-conditioner is on.

31. Ways to save energy
• Turn off the lights when you leave a room.
• Use only rechargeable batteries that are used
many times.
• Use more imaginations and less electronic
games.
• Ask your parents to use energy saving light
bulbs.

32. More imagination
Rechargeable batteries
Saving light bulbs