# Wires and Components

In this worksheet, students will answer questions about the flow of electricity through a circuit and how it affects the components in that circuit.

Key stage:  KS 2

Curriculum topic:   Electricity

Curriculum subtopic:   Variations in Functions of Components

Difficulty level:

### QUESTION 1 of 10

Finding out about electricity, what it does and how it does it, is fascinating.  Not only that, but it's such a mega-important part of our lives, understanding it better is vital!  That's one of the reasons you get to test out electric circuits at school (and at home if you're lucky enough to have a kit!).

In a simple series circuit (where the components are connected in one complete loop) the flow of electricity (the current) is affected by the wires and components.

Adding more components results in less current for each one. This makes bulbs dimmer and motors slower.

FACT: it is harder for current to flow through long, thin wires.

FACT: short, thick wires make it easier for the current to flow.

OK, with all that in mind, let's have a look at current, wires and components.

A simple, complete loop circuit is called a...

circle circuit

series circuit

cereal circuit

In a circuit, the motors, bulbs, batteries and buzzers are...

compounds

complicated

components

What is the name of the clips used to connect the wires to the components?

alligator

crocodile

metal

The amount of electrical energy produced by a battery is measured in...

Volts

Watts

Amps

Which ONE of these statements is TRUE?

electricity always flows easily through wires

thin wires make it easier for current to flow

thick wires make it easier for current to flow

Which ONE of these statements is TRUE

short wires make it harder for the current to flow

long wires make it harder for the current to flow

the length of the wire does not affect flow

In a series circuit, made using one bulb and one battery, which TWO variables will make the bulb dimmer?

using short, thick wires

using long, thin wires

In the same series circuit, the bulb is replaced with a motor.

Which THREE variables will affect the speed of the motor?

the thickness of the wires

the strength of the battery

the crocodile clips

the length of the wires

To test the effect of thin against thick wires in an identical circuit, Kelly uses a 7cm length of thin wire and a 10cm length of thick wire.

Is her test FAIR?

yes

no

Help Kelly decide which THREE variables she must keep the same in her fair test for:

"How the thickness of the wire affects the electrical current."

length

thickness

the bulb

the battery

First, Kelly uses a 10cm length of thick wire. Next, she uses a 10cm length of thin wire in the circuit.

Predict what will happen to the bulb when she connects the thin length of wire into her circuit compared with the thick wire.

the bulb will 'blow' - break

the bulb will be brighter

the bulb will be dimmer

the glass will melt

• Question 1

A simple, complete loop circuit is called a...

series circuit
EDDIE SAYS
Series - that's like programmes on the TV with, say, a series of 7 hour-long programmes in Sir David Attenborough's "Blue Planet II". So, in a circuit with components in a loop (cells/bulb/motor/bulb), that's a series circuit. The current has to flow through all of them, in a loop.
• Question 2

In a circuit, the motors, bulbs, batteries and buzzers are...

components
EDDIE SAYS
They're all examples of components - electrical things that get plugged into the circuit.
• Question 3

What is the name of the clips used to connect the wires to the components?

crocodile
EDDIE SAYS
Crocodile clips - makes sense, really. They appear to have jaws with teeth in - that's just to grip the component or wire firmly really.
• Question 4

The amount of electrical energy produced by a battery is measured in...

Volts
EDDIE SAYS
Any of these answers might seem OK, but the amount of electrical charge produced by a battery is measured in Volts. Batteries always have a mark on them to show their voltage, like 1.5V or 9V. That's how much electrical energy they can push out. Amps is a measure of the speed of the current around a circuit and watts is to do with electrical power output.
• Question 5

Which ONE of these statements is TRUE?

thick wires make it easier for current to flow
EDDIE SAYS
Thick wires are able to carry more current than thin wires. Think of it like water in a hosepipe: if you stand on the hosepipe, is it easier or harder for water to get down it? What about if you stick a narrower pipe into the end? See - that's like thick wires and thin wires - thicker wires can carry more electrical current.
• Question 6

Which ONE of these statements is TRUE

long wires make it harder for the current to flow
EDDIE SAYS
More energy is needed to flow along longer wires, leaving less current for the component. Again, comparing it with a hosepipe - if it was really, really long, it's going to be a lot harder for the tap to be able to get water along the whole length of the hosepipe, compared with a short length. That makes sense really, doesn't it? Works very similarly in electric current - that's why those giant cables strung between pylons, that carry electricity from the power station, manage to lose quite a bit of power before the current ever reaches your home.
• Question 7

In a series circuit, made using one bulb and one battery, which TWO variables will make the bulb dimmer?

using long, thin wires
EDDIE SAYS
Another bulb and long, thin wires will use more energy from the battery, making the bulb dimmer. Another battery will give more electrical 'push', so that's not right, and short wires carry more current. Adding components slows the current down (= dimmer bulb) and so does having longer/thinner wires.
• Question 8

In the same series circuit, the bulb is replaced with a motor.

Which THREE variables will affect the speed of the motor?

the thickness of the wires
the strength of the battery
the length of the wires
EDDIE SAYS
The speed of the motor depends on the amount of electrical energy, or current, reaching this component. Wire thickness, battery strength and the length of the wires all affect the current. Crocodile clips are only contacts, so they won't.
• Question 9

To test the effect of thin against thick wires in an identical circuit, Kelly uses a 7cm length of thin wire and a 10cm length of thick wire.

Is her test FAIR?

no
EDDIE SAYS
No - why's that? In a fair test only ONE variable must be changed, so if Kelly is changing the wire's thickness, she MUST keep the same length of wire. Otherwise, if her results show a different current, how will she know what caused the change: thickness or length? Getting this right in your investigations is really important.
• Question 10

Help Kelly decide which THREE variables she must keep the same in her fair test for:

"How the thickness of the wire affects the electrical current."

length
the bulb
the battery
EDDIE SAYS
Only the variable being investigated changes - for this test it's the thickness of the wire only. That means if she is changing the wire's thickness she MUST keep the length of the wire the same, use the same battery and the same bulb. Then, if her results show there is a change, she knows it must have been the change in the wire's thickness that caused the current to be different.
• Question 11

First, Kelly uses a 10cm length of thick wire. Next, she uses a 10cm length of thin wire in the circuit.

Predict what will happen to the bulb when she connects the thin length of wire into her circuit compared with the thick wire.

the bulb will be dimmer
EDDIE SAYS
Remember, it's harder for the battery to push the current through the thin wire. So, the thin wire will reduce the current and make the bulb dimmer. Got all that?
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