Magnets

Magnet Activity #1

What will move a magnet? Test the items listed below to see if they can make the magnet move. The next slide will reveal the answers. Button Nickel Nuts & Bolts Scissors Marble Penny Paper Clip Pencil NoYes Item

What will make a magnet move? Button Nickel Nuts & Bolts Scissors Marble Penny Paper Clip Pencil NoYes Item

Paper clips attract... because they are made of iron.

Scissors attract. because they are made of iron.

Nuts and bolts attract. because they are made of iron.

Magnets in my house Refrigerator magnets Headphones Telephone receivers Phone ringers Seal around refrigerator door Credit card magnetic strip Computer monitor, hard drive, speakers Shower curtain weights Power supply transformers TV deflection coil Microwave tubes

Caused by electron spin An object in which all domains are aligned in the same direction Composed of ferromagnetic material (iron, nickel, cobalt, gadoliniuim). What is a magnet?

What are magnetic domains? Magnetic substances like iron, cobalt, and nickel are composed of small areas where the groups of atoms are aligned like the poles of a magnet. These regions are called domains. All of the domains of a magnetic substance tend to align themselves in the same direction when placed in a magnetic field. These domains are typically composed of billions of atoms.

Magnetized Objects Unmagnetized Magnetized

For every North, there is a South If you take a bar magnet and break it into two pieces, each piece will again have a North pole and a South pole. SNSNSN No Monopoles Allowed - It has not been shown to be possible to end up with a single North pole or a single South pole, which is a monopole S N

a material that is easily magnetized and loses its magnetism quickly Temporary Magnet VS Permanent Magnet materials that are hard to magnetize and will also stay magnetized for a long time

Magnetic Field Lines Magnetic field lines can be drawn in the direction a north pole of a compass needle would point if placed at that point. The number of lines per area show the strength of the field at that point.

Uses of magnets Magnets were first put to use in navigation because they always point north and south. Magnets are used to hold, separate, control, convey and elevate products and to convert electrical energy into mechanical energy or convert mechanical energy into electrical energy.

Ways to demagnetize a magnet 1.) Strike the magnet with force 2.) Heat it

The earth is like a giant magnet! The nickel iron core of the earth gives the earth a magnetic field much like a bar magnet.

We use the Earth’s magnetic field to find direction. The needle of a compass always points toward the magnetic south pole. We call this direction “North” (remember, opposites attract)

Activities #2 - #4 Supplement – What is in your breakfast

Electricity and Magnetism – how are they related? 1.) When an electric current passes through a wire a magnetic field is formed. 2.) when a wire is moved across a magnetic field, an electric current is induced in the wire

Demos & Activities Magnet from electricity ELECTROMAGNET Electricity from magnets ELECTRICAL INDUCTION See Activity #4

In general, who has a better sense of direction? 1.Males 2.Females

Fun Fact Humans have a small number of very tiny iron filings in the bone and cartilage of the nose, right in the center near the eyes. There is evidence that people can use these filings to orient themselves toward magnetic north even when blindfolded. MALES tend to have more of these filings, which explains why males tend to be better at geographic orientation (and why females tend to rely more on street names and other identifiable features).

Fun with Magnets