New
New
Year 8

Measuring electric current

I can measure current and describe the rule for current in a series circuit.

New
New
Year 8

Measuring electric current

I can measure current and describe the rule for current in a series circuit.

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Lesson details

Key learning points

  1. An ammeter is used to measure the size of an electric current.
  2. An ammeter measures the current flowing through it without affecting the current in the circuit it is connected into.
  3. Electric current is measured in amps (A), which is short for amperes.
  4. The current in a series circuit is the same everywhere.
  5. Adding a component to a series circuit changes the current everywhere, on both sides of the component.

Keywords

  • Ammeter - An ammeter is a device that measures the current flowing in a circuit.

  • Amp - An ammeter measures the current in units called amps (A) which is short for amperes.

  • Series circuit - An ammeter is always placed in a series circuit so the electric current has to pass through it.

Common misconception

Pupils hold a consumption model of electric current in which it is used up in a circuit. They misuse the terms: voltage, current and electricity and choose a voltmeter to measure current.

Get pupils to investigate the size of current through a range of different conductors (and insulators) with an ammeter in a simple circuit. This will help them familiarise themselves with it and its use.

Get pupils to predict what they will find and then compare these predictions with their findings. Encourage them to test their predictions and then reason why they are (in)correct. This can be facilitated through class discussion. Additional circuits can be tested as an extension to task A.
Teacher tip

Content guidance

  • Risk assessment required - equipment

Supervision

Adult supervision required

Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

Lesson video

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6 Questions

Q1.
What is the name of the tiny charged particles that flow round a circuit?
protons
neutrons
hadrons
Correct answer: electrons
Q2.
What is the name of the component that can be closed (to allow current to flow) or open (to stop current flowing)?
a bulb
a battery
an ammeter
Correct answer: a switch
a resistor
Q3.
What is the word used to describe a flow of charge?
voltage
Correct answer: current
resistance
capacitance
Q4.
Where do electrons enter a battery?
Correct answer: the positive terminal
the negative terminal
both the positive and negative terminal
electrons only leave a battery - they don't enter it
Q5.
Where would you find electrons that can flow to cause a current? Choose all that apply.
Correct answer: the metal wire in a circuit
Correct answer: a resistor
the plastic of the leads
Correct answer: a battery
Correct answer: a bulb
Q6.
Match the electrical circuit terms to the correct meanings.
Correct Answer:electron,a tiny negatively charged particle

a tiny negatively charged particle

Correct Answer:charge,this can be either negative or positive

this can be either negative or positive

Correct Answer:battery,a component that pushes out and pulls in electrons

a component that pushes out and pulls in electrons

6 Questions

Q1.
Which photo shows an ammeter?
An image in a quiz
An image in a quiz
An image in a quiz
Correct Answer: An image in a quiz
An image in a quiz
Q2.
What happens to the current in a series circuit?
it decreases as it passes through components
it increases as it passes through components
Correct answer: it stays the same as it passes through components
it decreases as it passes through components then goes back to the original
Q3.
What will happen to the current when an ammeter is placed in a series circuit?
it will increase
Correct answer: it will stay the same
it will decrease
it is placed before the battery it will increase, if after, it will decrease
Q4.
Which statement is true about this circuit?
An image in a quiz
Correct answer: the ammeters have no effect on the current
the lamp has no effect on the current
the lamp reduces the current and the ammeters increase the current
both the lamp and the ammeters reduce the current
Q5.
What statement is correct about the readings on the two ammeters?
An image in a quiz
ammeter 1 will be higher than ammeter 2
ammeter 1 will be lower than ammeter 2
ammeter 1 will be positive and ammeter 2 will be negative
Correct answer: both ammeters will read the same current
Q6.
What statement is true about the lamps?
An image in a quiz
Correct answer: they will all be equally bright
lamp 1 will be brightest followed by lamp 2 and lamp 3 will be dimmest
lamp 3 will be brightest followed by lamp 2 and lamp 1 will be dimmest
lamps 1 and 3 will be the brightest and lamp 2 will be dim