Combined Science (1-9): Electromagnetism Electromagnetism

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Draw a line under last lesson’s work and write today’s title in your book... Electromagnetism 14/11/2018 c/w

FLASHBACK FLASHBACK: Explain what is meant by acceleration and how it can be determined experimentally for someone running a race

FLASHBACK- AFL FLASHBACK: Explain what is meant by acceleration and how it can be determined experimentally Acceleration is the rate of change of speed (change in speed over time) You could have the runner run around the track taking their speed at two different points This could be taken by using speed=distance / time Distance determined by using a tape measure Time recorded with a stopwatch/clock Acceleration= v-u/t

Draw a radial electric field and a uniform magnetic field Starter Activity Draw a radial electric field and a uniform magnetic field

Describe what you observe and suggest an explanation Explore: Electromagnetism Task: This diagram shows a wire passing through a piece of paper carrying a current. On the paper are iron filings. Describe what you observe and suggest an explanation A current flowing through a wire produces a magnetic field around the wire. Iron filings can be used to visualise this field as they line up along the field lines.

The pattern of field lines (flux) around this wire is circular Explore: Electromagnetism The pattern of field lines (flux) around this wire is circular You can determine the direction of the field (clockwise/anticlockwise) by making a ‘thumbs up’ with your right hand When your thumb follows the direction of current, your other fingers show the direction of the field. This is Fleming’s RIGHT hand rule

Explore: Solenoids (coils) If a wire that carries a current is coiled (solenoid) into a spring-shape, the field around the coil ends up looking a little different Task: Suggest by sketching, what the field will look like around/within a solenoid Due to the current travelling in different directions on each side of a coil, the two fields partly oppose resulting in a constant field in the centre

Explore: Electromagnets Due this constant field inside the solenoid, you can induce magnetism upon iron by placing some iron in the coil (temporary magnet) Task: Suggest what could be changed in the set-up shown to make the induced magnet stronger Task: How could we determine the strength of the magnet experimentally?

Explore: Testing Electromagnets Use the equipment provided to answer the following experimental question: Q: How does changing the number of coils around the iron affect its strength?

6 mark question! Explain what a solenoid is and define the difference between a permanent magnet and a temporary magnet

6 mark question! A solenoid is a coil of wire Explain what a solenoid is and define the difference between a permanent magnet and a temporary magnet A solenoid is a coil of wire It generates a magnetic field when current flows through it The direction of this field can be determined by Fleming’s Right Hand rule A permanent magnet always produces a magnetic field This field will attract magnetic materials (poles) When attached, the field induces a magnetic field in magnetic materials This turns them into temporary magnets

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