Magnetic Stir Bar

It's a paperclip compass.

A magnetic stir bar retriever can be used to retrieve magnetic stir bars from containers. The retriever is a bar with a magnet at the end which attracts the stir bars.

Magnetic Stir Bar Retriever

Compass.

Distance also plays a role. Think back to playing with a magnet.

JH Now is this electromagnetic here, or are these static?

We have to generate an electromagnetic field...

I need a compass.

Compass needles point to the north.

This is a large pulley made by sandwiching rubber between two old CDs.

No compass?

Magnetic stir bars are highly chemically inert, small magnetic bars. Most heaters have a built in magnet which can rotate this causes the stir bar to rotate and the mixture to become homogenized.

A magnet attracts iron.

This is a horseshoe magnet.

JH I agree.

In other words, the field of the magnet is near the pigeon's head.

The magnets, of course, have a magnetic field around them.

And the closer they are, the stronger the attraction.

Whenever current flows through the coil, this becomes an electromagnet.

You can see, this is the generator. It's a crank generator.

Charles Walcot investigated the magnetic compass bearing sense in pigeons.

This is a picture about a year ago.

I have here a superconductor, which I wrapped up so it'd stay cold long enough.

It includes 330 compasses.

Therefore it has a smaller gravitational pull on the astronaut.

Now this is important for two reasons.

I've got some pieces of notebook paper folded up into a rough Z shape.

It's a remarkable effect. It's very strong.

If you float a one yen coin on water and move a magnet slowly towards it then the coin will approach the magnet.

Keeton put magnets on the heads of his pigeons.

The magnets on their heads were responsible for that.

Maybe one more thing might help. Have you ever played with two magnets?

You know, the magnets with the north and the south poles?

This is a permanent magnet.

The thieves made off with the jewels.

In order to get through that, we have to generate an electromagnetic field.

Ought to be called cavities on a stick.

All right, in order to get through that, we have to generate an electromagnetic field...

To have an electromagnetic field with the force that we want, we're gonna need at least a couple of car batteries.

Now that's more impressive when you consider those magnets weigh over 20 tons, and they moved about a foot.

So I'm sure all you engineers know that even though aluminum is a metal, it's not a magnetic material.

As you're seeing this gel magnet for the first time, if you assume that all magnets had to be hard, then seeing this surprised you and it changed your understanding of the way magnets could work.

But where is this compass?

These are these arrays.