# Circuit Basics 2

In this worksheet, students will be taken through some further fundamental concepts underpinning their understanding of electric circuits.

Key stage:  KS 2

Curriculum topic:   Electricity

Curriculum subtopic:   Variations in Functions of Components

Difficulty level:

### QUESTION 1 of 10

OK, so you know how much we depend upon electricity in our modern world. That's only going to increase as the world moves forward, so having a solid understanding of the basics about electricity and how circuits work makes good sense.

This worksheet takes you through some more of those foundation ideas to help you get them sorted. OK, let's go for it!

Ali made a circuit using a 1.5V cell, a wire, a bulb and some clips.

He clipped different objects into the circuit to see whether electricity would go through them and make the bulb light up.

Which of the following objects do you think made Ali's bulb glow?

brass key

aluminium foil

plastic ruler

magnet

steel paperclip

shoelace

eraser

50p coin

playing card

tin of baked beans

china mug

Ali found that when objects allowed electricity through them the bulb lit up.

What do we call materials that allow electricity to pass through them?

resistors

conductors

insulators

Ali found that several objects in question 1 failed to make the bulb light when they were connected into the circuit.

This was because the materials they are made of are a type of what?

Resistor

Conductor

Insulator

Ali took a pencil and sharpened both ends of it.

He then carefully connected his clips onto the sharpened ends of the pencil lead and found that his bulb lit up.

Why do you think this happened?

Light switches in bathrooms are often turned on and off using a long string. This is to prevent people touching the switch with wet hands.

Why could that be a bad thing?

wet hands would slip on a normal switch

touching the switch with wet hands could give you an electric shock

water could get into the switch and break it

When you plug something into an electrical socket one thing you notice is that the wire is not bare - it's covered in a type of plastic.

What is the best explanation for this?

to protect you from getting an electric shock

the colour of the wire shows you what you're plugging in

to protect the copper wire from being damaged

to make it easy to handle

to help the electricity go through the wire

Ali discovers that one of his wires has been damaged and he can see the metal wire inside.

He needs to mend the wire. Which of the following do you think would be the best choice for Ali to use to mend the damaged wire?

sticky plastic tape

aluminium foil

string

superglue

Different sorts of electrical appliances can be plugged into mains sockets. If something goes wrong it is possible to get an electric shock from it.

If you hold an ordinary battery in your hand it doesn't give you an electric shock.

Why do you think you don't get a shock?

human bodies don't conduct electricity

batteries are too small to hurt you

batteries only produce a small voltage

Ali connected a 1.5V battery to a 1.5V bulb and the bulb glowed with normal brightness.

Ali then started to add more 1.5V batteries to the circuit, in series with his first battery. He noticed that the bulb glowed brighter.

If Ali keeps on adding batteries what do you think will happen?

the bulb will glow so brightly that Ali will find it difficult to look at

the filament in the bulb will burn out

the bulb will get brighter to start off with and then stay at the same brightness

In his experiment Ali joined the batteries to the bulb with bare copper wire.

What do you think is the best explanation for why it was safe for him to do this?

the wire won't get hot

there's not enough voltage to be dangerous

the current is very low

• Question 1

Ali made a circuit using a 1.5V cell, a wire, a bulb and some clips.

He clipped different objects into the circuit to see whether electricity would go through them and make the bulb light up.

Which of the following objects do you think made Ali's bulb glow?

brass key
aluminium foil
magnet
steel paperclip
50p coin
tin of baked beans
EDDIE SAYS
Basically if it's made of metal it'll conduct electricity; if it's not metal it won't. There are very few exceptions.
• Question 2

Ali found that when objects allowed electricity through them the bulb lit up.

What do we call materials that allow electricity to pass through them?

conductors
EDDIE SAYS
Conductors conduct electricity - simple!
• Question 3

Ali found that several objects in question 1 failed to make the bulb light when they were connected into the circuit.

This was because the materials they are made of are a type of what?

Insulator
EDDIE SAYS
Non-metallic materials (plastics, wood, paper, etc.) do not conduct electricity and so are insulators.
• Question 4

Ali took a pencil and sharpened both ends of it.

He then carefully connected his clips onto the sharpened ends of the pencil lead and found that his bulb lit up.

Why do you think this happened?

EDDIE SAYS
Yes, all metals conduct but pencil lead is not metal. That's confusing because 'lead' is a metal! However pencils contain a form of carbon called GRAPHITE which used to be known as 'black lead', hence the name pencil lead. Graphite is a non-metal that will conduct electricity.
• Question 5

Light switches in bathrooms are often turned on and off using a long string. This is to prevent people touching the switch with wet hands.

Why could that be a bad thing?

touching the switch with wet hands could give you an electric shock
EDDIE SAYS
Although it's fairly unlikely, you could get an electric shock by touching something electrical with wet hands. That's because water is a weak conductor and could make a connection between skin and voltage, causing a shock.
• Question 6

When you plug something into an electrical socket one thing you notice is that the wire is not bare - it's covered in a type of plastic.

What is the best explanation for this?

to protect you from getting an electric shock
EDDIE SAYS
Although there might seem some sensible ideas here the over-riding one is for your safety: the insulation is to keep you and the electricity flowing down the wire apart.
• Question 7

Ali discovers that one of his wires has been damaged and he can see the metal wire inside.

He needs to mend the wire. Which of the following do you think would be the best choice for Ali to use to mend the damaged wire?

sticky plastic tape
EDDIE SAYS
Insulating tape is a type of sticky plastic tape that's designed for wrapping around broken insulation that surrounds the electrical cable. It doesn't conduct electricity (which the foil would) and is flexible.
• Question 8

Different sorts of electrical appliances can be plugged into mains sockets. If something goes wrong it is possible to get an electric shock from it.

If you hold an ordinary battery in your hand it doesn't give you an electric shock.

Why do you think you don't get a shock?

batteries only produce a small voltage
EDDIE SAYS
In fact human bodies do conduct electricity, just not that well. A standard battery produces 1.5V of DC current which has nowhere near enough 'push' to get any meaningful current through you. The mains voltage of 230V produces a much larger AC current which could get through your body and damage you, especially if your skin is wet; so no using the hair-dryer in the bathroom!
• Question 9

Ali connected a 1.5V battery to a 1.5V bulb and the bulb glowed with normal brightness.

Ali then started to add more 1.5V batteries to the circuit, in series with his first battery. He noticed that the bulb glowed brighter.

If Ali keeps on adding batteries what do you think will happen?

the filament in the bulb will burn out
EDDIE SAYS
Basically as Ali keeps on adding batteries the current increases until it is so high that the bulb 'blows', or goes out, because the tiny wire filament inside has melted. The filament is what 'glows' inside a standard bulb because the electric current is making it hot. If the current makes it too hot, the wire melts.
• Question 10

In his experiment Ali joined the batteries to the bulb with bare copper wire.

What do you think is the best explanation for why it was safe for him to do this?

there's not enough voltage to be dangerous
EDDIE SAYS
In fact, the wire can get quite hot with all those batteries (depends on how thin it is) and the current is probably quite high (probably over 1A) but the 1.5V batteries, even if there are five or six, still won't produce a voltage that could harm Ali.
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