1. ENERGY
Grade 8
Integrated Science

2. Give examples of the various kinds of energy
Objectives
Define energy and fuel
Give examples of the various kinds of energy
Show how energy is converted
Distinguish between renewable and non-renewable energy
Discuss uses of the sun’s energy
Draw the electromagnetic spectrum
Discuss the harmful effects of the sun’s energy
Describe how crude oil is formed
State the uses of crude oil and other fuels
Discuss the importance of energy conservation
List ways of conserving energy
Calculate Energy efficiency

3. WHAT IS ENERGY? Energy is the ability to do work
Energy can also be considered as the ability to bring about a change

4. TYPES OF ENERGY? Kinetic/movement energy (KE)
Potential/stored energy (PE)
Electrical energy
Chemical energy (CE)
Solar energy
Nuclear energy
Light energy
Heat energy
Sound energy

5. THE LAW OF ENERGY CONSERVATION
ENERGY CONVERSION
THE LAW OF ENERGY CONSERVATION
Energy can neither be created nor destroyed, but can be changed or converted from one form to another.

6. A BLENDER CHANGES ELECTRICAL ENERGY INTO MOVEMENT ENRGY SOUND AND HEAT
ENERGY CONVERSION
A BLENDER CHANGES ELECTRICAL ENERGY INTO MOVEMENT ENRGY SOUND AND HEAT
Sound energy
Electrical Energy
Heat energy
Movement energy
BLENDER

8. ENERGY FROM THE SUN The sun is a huge ball of ‘burning gas’
It has a very high temperature of approximately 150 million degrees Celsius at its centre.

9. USES OF THE SUN’S ENERGY
Vitamin D
Provides light
Provides heat which sustains life
To grow food
To dry clothes
To produce electricity

10. ELECTROMAGNETIC SPECTRUM

11. HARMFUL EFFECTS OF THE SUN’S ENERGY
Sun Burn
Heat Stroke
Cataract
Heat Rash
Skin cancer
Ages skin

12. CRUDE OIL
crude oil is a mixture of complex hydrocarbon molecules and other organic compounds.
Another name used for this material is petroleum, although that term also refers to products made from refined material itself.

13. CRUDE OIL
Crude oil exists as a liquid found in various formations deep within the Earth’s crust.
This liquid forms as a result of the decomposition of organic material that dates back millions of years, and are known as fossils.

14. Oil rig which is used in the extraction of crude oil.

15. Extraction of crude oil
Extraction of crude oil. The lightest gases will come off fist and the heaviest substance (heavy oils) will come off last the others fall in the middle the substances are separated based on density (how heavy they are

16. USES OF CRUDE OIL

17. ENERGY EFFICIENCY Energy efficiency is not energy conservation.
Energy efficiency is "using less energy to provide the same service".
Energy efficiency is not energy conservation.
Replacing an incandescent lamp with a compact fluorescent lamp (which uses much less energy to produce the same amount of light) is energy efficiency.

18. Energy usage/usable energy is also the work done
ENERGY EFFICIENCY
Energy usage/usable energy is also the work done

19. The efficiency of the hammer strike was 40%.
ENERGY EFFICIENCY
Efficiency Formula Questions:
1) A construction worker puts 20 J of energy in to one strike of his hammer on the head of a nail. The energy transferred to driving the nail in to the wood is 8.0 J. What is the efficiency of the construction worker's hammering?
= 0.40 x 100%
= 40%
The efficiency of the hammer strike was 40%.
Vibrations and heating of the nail are two possible reasons for the energy loss

20. ENERGY EFFICIENCY Energy is measured in joules.
However, if you are given the mass and height of an object you can calculate the energy using the formula
Mass X height X gravity (where gravity = 10)

21. ENERGY EFFICIENCY
A ball of mass 0.2 kg is thrown vertically upwards and reaches a height of 15m. When the ball hits the ground it bounces to a height if 5m. Find:
The energy of the ball when thrown up
Mass (0.2) X height (15) X gravity (10) = 30 J
b) The energy of the ball on rebound( when it hits ground and bounce)
Mass (0.2) X height (5) X gravity (10) = 10 J
c) The energy lost when ball hits the ground
Energy input = useful energy + lost energy
30= 10 + x therefore the energy lost is 20 J
30-10= 20 J

22. ENERGY CONSERVATION
Energy conservation is reducing or going without a service to save energy.
For example:
Turning off a light is energy conservation.