Year 9 - Science
Current through an electromagnet
Magnets and electromagnets
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This pupil-friendly study guide includes a unit summary, clear notes, common mistakes, and quick questions with answers.
Unit Summary
This unit explores magnetism, including magnetic poles, fields, and Earth's magnetism, along with the principles of electromagnets and DC motors. It focuses on conducting precise scientific enquiries and identifying variables and emphasises accuracy, repeatability, and reproducibility.
Lesson Summary
You will learn to plan an experiment to test the strength of an electromagnet and explain how different factors affect the strength of an electromagnet.
Key Notes
- The more turns of wire in the coil of an electromagnet, the stronger its magnetic field.
- The greater the current through the coil of an electromagnet, the stronger its magnetic field.
- The more closely spaced the coils of wire of an electromagnet, the stronger its magnetic field.
- An electromagnet made from bare wire will not work if adjacent turns are touching.
- A soft iron core increases the strength of an electromagnet because it becomes magnetised when it is turned on.
Vocabulary To Learn
- independent variable: the variable that the person doing the experiment changes
- dependent variable: the variable that the person doing the experiment measures
- control variable: the variables that may affect the dependent variable and should be kept the same
- fair test: an experiment where the control variables are kept the same
- soft iron core: the centre of a strong electromagnet that becomes magnetised
Common Mistakes To Avoid
- Pupils often refer to the turns of a coil as the number of coils.
3 Quick Questions (With Answers)
1. Explain the scientific idea in this lesson using two key points.
The more turns of wire in the coil of an electromagnet, the stronger its magnetic field. The greater the current through the coil of an electromagnet, the stronger its magnetic field.
2. Define this scientific word and use it in context. 'independent variable'
the variable that the person doing the experiment changes. Include the word in a full scientific explanation, not as a single label.
3. Correct this common scientific misunderstanding.
Mistake: Pupils often refer to the turns of a coil as the number of coils. Correction: Emphasise that turns of wire can be added to a coil to make the coil longer.
More Lessons In This Unit
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