1. Do now! Do you know the formulae for Wenesday’s Test? D = m/V p = F/A p = ρhg p 1 V 1 = p 2 V 2 (constant temp and fixed mass) p 1 /T 1 = p 1 /T 1 (constant volume and fixed mass) Henry (aged 8¾)

2. What do you need to know about magnets?

3. ALL magnets have two poles NORTH seeking pole SOUTH seeking pole

4. Breaking a magnet produces two magnets! NS NS NNSS

5. Opposites attract!

6. Opposite poles attract and like poles repel

7. Magnetic materials

8. Iron (steel), Cobalt and Nickel

9. Magnetic induction

10. When a magnetic material is close to a magnet, it becomes a magnet itself We say it has induced magnetism N S N S magnet

11. Hard and Soft Magnetism

12. Soft Magnetism Pure iron is a soft magnetic material It is easy to magnetise but loses its magnetism easily N S beforeafter Iron nail S N N S Not a magnet N

13. Hard Magnetism Steel is a hard magnetic material It is harder to magnetise, but keeps its magnetism (it is used to make magnets!) N S beforeafter Steel paper clip N N S It’s a magnet! N S SN

14. Magnetic fields I wonder if this is a magnetic field?

15. Magnetic fields Magnets (and electric currents) produce magnetic fields around them. In the magnetic field, another magnet or magnetic material will experience a magnetic force.

16. Magnetic field lines We can represent the magnetic field around a magnet using field lines.

17. Magnetic field lines The arrows show the direction a compass needle would point at that point in the field.

18. Magnetic field lines The closer the field lines are, the stronger the magnetic force felt The arrows show the direction a compass needle would point at that point in the field.

19. Mind-map Ms Weston will put these slides on a loop and you are going to mind-map them (Colours, drawings, single words)

20. Plotting magnetic fields

23. 1. Two magnets, opposite poles facing each other 6 cm apart 2. Two magnets, like poles facing each other 6 cm apart 3. Two magnets along side each other, 5 cm apart, opposite poles opposite each other.

24. Field around a bar magnet

25. Two bar magnets Strong uniform field

26. Two bar magnets no field!

27. Earth’s Magnetic Field N S Remember the North of a compass needle points to the geographic north pole (i.e. the geographic North pole is a magnetic south pole!)