Agenda 5/18

• Circular Motion Warm-Up• Hand back GA Packets

• Demo: Disney Mythbusters• Notes: Magnets

• Conclusion: In-class Mythbusters

Disney Mythbuster

• https://www.youtube.com/watch?v=HFrCkt60A9w

It this really possible?

• Could Pluto swallow a magnet and still be able to pick up all kinds of metal things?

• What do you think?

• Why or why not?

Magnetism

• The physics behind magnets parallel the physics behind charge very well.

Electric Charges vs Magnets

• Positive & negative charges

• Like charges repel• Opposite charges

attract• Electric Fields

surround electric charges

• Can isolate a charge

• North (seeking) & south (seeking) poles• Like poles repel• Opposite poles attract• Magnetic fields surround magnets• Cannot isolate a pole

Different Types of Magnets

• Magnets come in many shapes and sizes. (bar magnets, circular magnets, horseshoe, etc.)

• No matter what the shape or size every magnet must have a north and south pole.

What happens if you break a magnet in half?

• If you break a magnet in half, each side will still have a north pole and a south pole.

• If you continued breaking the magnet into smaller and smaller pieces every piece will have a north pole and a south pole.

N S N S N SNS

More on Breaking Magnets

• This picture further shows what happens when a magnet gets broken in half.

• Breaking magnets can be purchased but we believe it works better to “fake” it.

Agenda 5/19/15

• Warm-Up• Finish Notes: Magnetism

• Electromagnets Activity– Paper clip activity

Magnetic Domains• This diagram represents an

unmagnetized iron nail. The arrows represent the alignments of the magnetic domains. These domains are not aligned.

• This diagram represents a bar magnet. The domains in the magnet are aligned.

How Does Something Become Magnetized?

• If you touch the nail to the bar magnet, the nail becomes magnetized.

• This is because the domains in the nail will now align.• If you remove the nail, the domains fall back out of

alignment and the nail loses its magnetism.

Magnetic Fields

• A magnetic field can be thought of as a field that shows magnetic force lines.

• You can easily show the magnetic field with iron filings and a magnet. The iron filings will line up with the magnetic field.

• Out of the South into the North

The Earth’s Magnetic Field

• The north pole of a compass seeks north because is aligns with the Earth’s magnetic field.

• What gets a bit confusing is the magnetic south is in the geographic north and vice versa.

• Scientists believe that the Earth’s magnetic field comes from convection currents in the liquid outer core.

Agenda 5/20/15

• Warm-Up

• Breakdown Electromagnets– Demo Electromagnets

• Complete Magnetic Fields

• 2nd Period: Research for Mouse Trap Car

Electromagnets

• Benefits:– Can be turned on and off by switch– Can be adjusted depending on use of magnet

• Drawbacks:– Must have a current supply– Potential for dangerous situations

• Fires, shorted circuits

Electromagnet Applications

• Motors

• Crane

• Projectiles

Magnetic Field Lines

• Which direction do the run??

Bar Magnet

Horseshoe Magnet

Ring Magnet

Problems

N S

S N

Problems

N S

N S

Agenda 5/22

• Two Tasks Today:

1. Complete the construction of your mousetrap car

2. Complete your semester 2 review guide– Cheat Sheet/Formula Sheet Allowed