Electricity Flashcards
What is electricity?
Electricity is a form of energy
Name three other forms of energy that electricity is usually converted to
. Light
. Movement
. Sound
For an appliance to work it needs a source of _________.
Energy
What is a cell?
They provide the energy needed for electrons to move around in an electric circuit
What does a circuit do?
A circuit provides a pathway for electricity to flow from an energy source, such as a cell, to where it is needed and back to the source
The pathway needs to form a _______ loop.
Closed
What is a circuit board?
Metal pathways printed on a board
Name three forms that electrical circuit can take.
Closed loop made of electrical wires
Circuit board
Pylons
Electric circuits are made of different parts. These parts are called _________.
Components
What are the components of an electric circuit?
. A source of energy
. Conducting material
. Devices
. Switches
What is “A source of energy”?
Each circuit needs a source of electrical energy. Cells and batteries are one source of electrical energy in an electric circuit.
What are the 2 sides of a battery called?
The positive and negative side
How do you connect 2 batteries correctly?
The positive side of one battery must be connected to the negative side of the next battery
What is “Conducting material”?
A materials that electricity can flow through
What do conducting materials do?
They carry the electric current from the energy source to the other parts of the electric circuit
What is an electrical current?
The movement of electric charges through a conductor
What are most conducting wires made of?
Copper
What are the wires usually covered by?
Plastic
Why are most wires covered in plastic
Plastic doesn’t conduct electricity
What is the layer of plastic called?
Insulation
Why are electrical wires insulated?
To keep the electrical current from flowing where it is not wanted
What is “Devices”?
Man-made objects made to do a specific job. Different devices are used in electric circuits to convert electrical energy to other forms of energy such as light, sound or movement.
Name some examples of devices.
Bulbs
Buzzers
Motors
Bulbs convert electrical energy into ________ energy.
Light
The light a bulb gives of is called the ________ energy.
Output
We say that a bulb is a/an __________ device.
Output
What are 3 types of bulbs?
Compact fluorescent bulb
Incandescent bulb
Torch bulb
What is a buzzer?
An electrical device that makes a buzzing sound
A buzzer converts the electrical energy to ________ energy.
Sound
Electric motors convert electrical energy into _________ energy.
Movement
What happens when electrical current passes through a motor?
It causes the shaft to spin
How can the spinning movement of the shaft be used?
Household appliances: fans, washing machines
Tools: drills, grinders
What do you call a circuit with gaps in it
Broken
What is a switch?
It can be added to a circuit to start and stop the flow of an electric current.
When are switches useful?
When you want to turn an appliance on or off without having to plug it in or unplug it
True or false.
All electrical appliances have switches.
True
What is a circuit diagram
Diagram of electric circuit, drawn using standard symbols for electrical components
What is the difference between a cell and a battery?
A battery is made up of two or more cells
Correct the sentence.
Most metals conduct electricity and so does water, including lemon water.
Lemon=salty
Why is it important to know which materials conduct electricity?
It can help you use electricity safely. It may even save your life!
Why do we get a shock when we touch an uninsulated wire?
Our bodies are made mostly of water. This means that we can conduct electricity. If electricity goes through a person’s body, it can cause serious damage or even kill the person
What should you use to put out an electrical fire?
NEVER PUT IT OUT WITH WATER!!
Use sand or a chemical fire extinguisher instead.
What are insulators?
Materials that do not allow electricity to go through
List some insulating materials.
Plastic
Rubber
Ceramics
Glass
Most other materials that are not made of metal
What do you do if the insulation of an electrical cord is damaged?
Replace the cord before the appliance is used again. It must be replaced by an adult who knows how to do it safely. A qualified electrician must work on damaged wiring in a household circuit
Transmission lines are attached to pylons by insulators. What are these usually made of?
Ceramic material or toughened glass
What do the insulators on pylons do?
Stop the electricity from going from the cables into the metal pylons
What is the input device for most circuits?
A battery
What types of energy does the falling water in a watermill go through?
Starts: potential energy
Turns to: movement energy that makes the wheel turn
What are the 3 parts of an electrical energy system?
Input
Output
Process
What is “input”?
What goes into the circuit
It can be the electrical energy from a battery or mains electricity
What is “output”?
What is released from the circuit
It can be light from a bulb or heat from the element of a heater
What is “process”?
The manner in which the input is changed into the output. For example, the electric current in a circuit heats up the element of a heater. Electrical energy is changed into heat
What can we use a systems diagram for?
To show what happens in an electrical system
What is mains electricity?
Electricity from a power station that is transferred in a circuit to our homes and back to the power station
What is the most common source of energy in SA?
Coal
