2. Magnetism

3. Warm-up: (Get a new warm-up page for this week) What exactly is a magnet? Describe a magnet in as much detail as possible. This week: Tomorrow – Lab – Magnetic Fields Wednesday – Review for TEST ON FRIDAY – CIRCUITS and OHM’S LAW Thursday – Electromagnetic Induction and Electromagnets (Possible Lab) Friday – TEST: CIRCUITS and OHM’S LAW

4. Notes: Properties of Magnets Essential Question: What are some of the basic properties of magnets?

5. What exactly IS a magnet? How do you know something is magnetic? What are some properties of magnets? What rules do magnets follow? Can we make/destroy magnets?

6. How do you know something is magnetic? Magnets attract ferromagnetic materials These are metals which are attracted by magnets Examples include Iron, Cobalt, Nickel and alloys of these metals. Magnets do NOT attract all maetals

7. What are some properties of magnets? Can you rescue the drowning paper clip? Magnets work even through plastic, paper and water.

8. Magnets create magnetic fields Magnetic field is the area around a magnet where its magnetic forces can be detected. The magnetic field can be seen by placing the magnet under a piece of paper with small iron filings on top.

9. Magnetic Field is strong where lines are dense and weak where lines are sparse Magnetic Field is strong where lines are dense and weak where lines are sparse NS

10. What are some properties of magnets? What would happen if you dipped a bar magnet into a box of paper clips? Where do most of the paper clips stick to on the magnet? Why?

12. What are some properties of magnets? Most of the clips would stick to the ends of the bar, as shown in the picture The magnetic effects are not the same throughout a magnet. This shows that the strongest effects are near the ends of the bar magnet. (Why?) Each end of the magnet is called a magnetic pole.

13. Magnetic Poles These are areas on the magnet where magnetism is concentrated (mostly on the ends of the magnet). These poles are called North are South poles respectively.

14. What are some properties of magnets? What happen if you cut a magnet in half? You get 2 magnets The basic magnet is a dipole, not a monopole

15. Magnets have magnetic poles Every magnet has both a North and South pole. What rules do you think magnets follow?

16. http://www.ndt- ed.org/EducationResources/HighSchool/Magn etism/twoends.htm

17. Law of magnetism It states that “Like Poles Repel and Unlike Poles Attract”.

18. How can you Find the N and S pole of a magnet using compass? If it is brought close to the "South" pole of the magnet, the "North" pointer of the compass will be attracted to the magnet. If it is brought close to the "North" pole of the magnet, the "North" pointer of the compass will be repelled and will point AWAY from the magnet, while the "South" end of the compass pointer will point to the magnet.

19. Can we make/destroy magnets? Where do magnets come from anyway?

20. How can you Make a paper clip into a magnet? Straighten it out into a wire. To magnetize, rub and tap one end of the wire against one end of the magnet; then, reverse the ends of the wire and repeat this on the opposite end of the magnet http://www.youtube.com/watch?v=tq-rqGaBIM0

21. Magnetic Domains A region in which many atoms have their magnetic fields aligned is called a magnetic domain. http://www.ndt- ed.org/EducationResources/HighSchool/Magn etism/magneticdomain.htm

22. How Magnets Attract A magnet near an unmagnetized piece of iron causes: – Growth of aligned domains in the iron – Rotation of domains to align with the magnetic field – Attractive magnetic force on the iron This causes the iron to become temporarily magnetized

23. Demagnetizing A magnet can be destroyed by hammering. Heating a piece of magnetized iron or steel strongly in a flame will demagnetize it.

24. How are magnets related to electric charge? BrainPop! Electromagnetic Induction Electromagnets