Skip to content
Dabour HubLEARN · PRACTICE · EXPLORESign inStudent

4.4Unit 9: Magnetism and electromagnets

Investigating electromagnets — Cambridge Checkpoint Physics 0893 Revision Notes & Topical Questions

5 min read 10 parts Lesson 4 of 4 1 quiz

📚 Cambridge Checkpoint Physics 0893 Hub / Topical Revision
🩺
100% Curriculum Specification Match Lesson Doctor Verified
The only platform with 100% curriculum specification match and verified interactive question banks.
0%read
Lesson summary

4.4 Investigating electromagnets — CHECKPOINT PHYSICS 0893 notes: Describe the factors that affect the strength of an electromagnet and how to investigate them.Coil — a coil of wireCore — a magnetic core inside the coilCurrent — an electric current flowing in the coilFactors = va…

  • Demagnetised
  • Not like clay
  • Strong examples
  • World record
  • Why a line graph
  • Core materials

Part 1 of 8What makes an electromagnet

Coil
  • Coil a coil of wire
Core
  • Core a magnetic core inside the coil
Current
  • Current an electric current flowing in the coil
Factors
Factors variables that affect the strength

Part 2 of 8Ways to increase the strength

FactorChange that makes it stronger
Number of turns in the coilMore turns
Current in the coilLarger current, for example more cells
Material of the coreSoft iron or some types of steel

Part 3 of 8Soft iron

Meaning
  • Meaning iron that is easily magnetised and easily demagnetised
Demagnetised
Demagnetised has lost its magnetism
Not like clay
  • Not like clay soft here has nothing to do with softness to touch

Part 4 of 8Measuring strength

Method
  • Method count how many magnetic objects such as paperclips the electromagnet can lift and hold
Force
  • Force the strength is shown by the force exerted on magnetic material
Strong examples
  • Strong examples a scrapyard electromagnet must be stronger than the one holding a toaster basket
World record
  • World record an electromagnet 4500 times stronger than a school bar magnet

Part 5 of 8Investigating the number of turns

1
Make an electromagnet with an iron nail and a set number of cells.
2
Wrap five turns of wire round the core.
3
Switch on and count how many paperclips it holds, then switch off.
4
Add five more turns and repeat.
5
Continue until no more turns fit on the core.
6
Repeat the whole investigation and average the results.

Part 6 of 8Results for number of turns

Table
  • Table record the paperclips held for each number of turns and calculate averages
Graph
  • Graph a line graph with the number of turns on the horizontal axis
Trend
  • Trend the more turns, the more paperclips held
Why a line graph
  • Why a line graph both variables are numbers that can change continuously

Part 7 of 8Investigating the core material

Core materials
  • Core materials iron, steel and non-magnetic materials of about the same diameter
Control
  • Control keep the coil, current and number of turns the same
Result
  • Result iron gives the strongest electromagnet and non-magnetic materials such as aluminium or wood give almost none
Chart
  • Chart a bar chart is used because the core materials are separate categories

Part 8 of 8Investigating the current

Change
  • Change vary the number of cells or the power supply setting
Control
  • Control keep the number of turns and the core material the same
Prediction
  • Prediction a larger current holds more paperclips
Safety
  • Safety switch on for the shortest possible time and switch off if the wire becomes hot

Key terms

TermMeaning
FactorA variable that affects something.
Soft ironIron easily magnetised and demagnetised.
DemagnetisedHaving lost magnetism.
CoilTurns of wire around a core.
CurrentFlow of electrons in the coil.

Avoid these mistakes

1
Changing several factors at once — change one and control the others.
2
Using any material as the core — a magnetic core such as iron is needed.
3
Leaving the electromagnet on between readings — it makes the cell run flat and the wire hot.
4
Using a bar chart for numbers of turns — a line graph shows the trend.

Last updated:

\n