Journal 4/30/14

1. Journal 4/30/14 What would you do if you had a super-powerful magnet? Objective Tonight’s Homework To learn how magnetism works and where it comes from none

2. Notes on Magnetism Magnetism comes from moving electricity. Inside every atom, we have electrons moving around. They turn every atom into a tiny magnet.

3. Notes on Magnetism Magnetism comes from moving electricity. Inside every atom, we have electrons moving around. They turn every atom into a tiny magnet. If we get a lot of atoms together, we may get something like this: The atoms can point any which way!

4. Notes on Magnetism If we look at something magnetic up close, all the atoms in a very small chunk will point the same way. This is called a magnetic domain. We draw this as a border with an arrow pointing toward the magnetic North. =

5. Notes on Magnetism If we look at something magnetic up close, all the atoms in a very small chunk will point the same way. This is called a magnetic domain. We draw this as a border with an arrow pointing toward the magnetic North. = Each domain is incredibly tiny but still contains trillions of atoms all aligned in the same way.

6. Notes on Magnetism In most objects, each domain points in a different direction. Each domain creates magnetism in a different direction. Like tug of war, the overall effect becomes zero. There’s magnetism, but it all cancels.

7. Notes on Magnetism In most objects, each domain points in a different direction. Each domain creates magnetism in a different direction. Like tug of war, the overall effect becomes zero. There’s magnetism, but it all cancels. In a magnet, however, all the domains point in the same direction. The effect builds and we get something with a definite north and south!

8. Notes on Magnetism What about things like paperclips, which aren’t magnetic but stick to magnets anyway?

9. Notes on Magnetism What about things like paperclips, which aren’t magnetic but stick to magnets anyway? Materials like this are said to be ferromagnetic. The domains in ferromagnetic materials are normally mixed up, but they line up when a magnet or magnetic field is nearby. This makes them temporarily become magnets. However, once the magnet is removed, the ferromagnetic domains go back to being mixed up.

10. Notes on Magnetism Ferromagnet starts with jumbled domains:

11. Notes on Magnetism Ferromagnet starts with jumbled domains: Magnet comes near and turns ferromagnet into magnet temporarily:

12. Notes on Magnetism Ferromagnet starts with jumbled domains: Magnet comes near and turns ferromagnet into magnet temporarily: Magnet is removed and ferromagnet goes back to having jumbled domains:

13. Magnetism Practice Problems • If we mixed iron with sand, how would you remove the iron?Explain why your solution works! • 2) Explain how even through all objects have electrons, not all objects are magnetic. • 3) If you place a chunk of iron near the north pole of a magnet, it will be attracted. Will this also work if you place the iron near the south pole of the magnet? Explain why or why not! • Make a list of at least 5 things that would stick to a refrigerator if the door of it was made of permanently magnetized metal. • Why are metals ferromagnetic but things like skin and wood aren’t?

14. Exit Question #44 Every object has magnetism in it. True or false? a) True b) False