Science Pages 36-40

Question 1

National grid

Answer 1

Electrical system that supplies electricity to all parts of South Africa

Question 2

Nuclear material

Answer 2

An energy source found in atoms in Chemical elements such as uranium

Question 3

Sources of energy for electricity

7marks

Answer 3

Coal
Oil
Gas
Nuclear material 
Falling water
Wind
Sunlight

Question 4

Generator

Answer 4

A machine that other types of energy into electrical energy

Question 5

Turbine

Answer 5

A machine that uses energy in water or steam to make it turn

Question 6

Transformer

Answer 6

A machine that changes the voltage of electricity

Question 7

In SA most of our electricity is made at power stations that

Answer 7

Burn coal

Question 8

SA has rich deposits of coal

True False

Answer 8

True

Question 9

How electricity is made at a power station

Answer 9

1. coal is burner in a boiler 2 boil water which makes steam
2. the high pressure steam is passed through a turbine which contains a large wheel with blades like a fan
3. the energy in the steam turned the wheel in the turbine
4. the turbine is connected to a shaft in a machine called a generator which turns.as the turbine wheel turns the energy in the generator shaft is converted into electrical energy
5. electricity is then transported into places like homes ,hospitals, and factories by big pylons and electricity cables
6. the electricity is changed into the correct voltage by a transformer. A transformer is an electrical device that can increase or decrease the voltage of electricity

Question 10

Dynamo

Answer 10

Small generator which changes the movement energy into electrical energy

Question 11

How 2 conserve electricity in our homes

Answer 11

.Always put the lid on the pot when cooking to stop heat loss
.cover the windows with curtains and put carpets on the floor to prevent heat loss
.dress warm and insulate your house so u don’t have 2 use a heater and use heat energy
.only put the amount of water in your kettle for the amount of tea you want 2 make so u don’t waste electrical energy
. Don’t put small pots or pans on big stove plates
.switch off lights , and other appliances such as radios, computers,TV sets, and heaters when not in use
.use energy saving lightbulbs they use less energy and prouduce more light
Save daylight hours go 2 bed early and wake up early 2 make use of natural light