| What Are Magnets? |
| #1 |
What is a magnet? |
an object that attracts certain kinds of metals, such as iron |
| #2 |
What are the ends of the magnet, where the force is greater, called? |
poles |
| #3 |
What is the name of one naturally occurring magnet? Hint: Shown at the beginning of the chapter. |
Lodestone (also acceptable: magnetite, iron oxide) |
| #4 |
Explain how poles are attracted or repelled by each other. |
magnetic poles of opposite types (north and south) attract. Poles of the same type repel (north and north or south and south). |
| #5 |
Why do farmers give their cows magnets to eat? |
Cows do not chew their food, so they often swallow metal objects. Magnets attract these objects so that the cows aren't injured by the objects. |
| Identifying a Magnetic Field |
| #1 |
What is a magnetic field? |
the area around a magnet in which magnetic forces can act |
| #2 |
What are lines of force? |
lines that show a magnetic field |
| #3 |
What type of magnet is the Earth? |
a bar magnet |
| #4 |
How does a compass use magnets to work? |
the compass needle is a magnet, as is the Earth. The north pole attracts the north arrow of the compass needle, and it is drawn toward the north pole. |
| #5 |
How would lines of force be shown if you put a magnet under a sheet of paper and iron fillings on top? |
the iron fillings will be attracted to the the magnetic lines of force and arrange themselves accordingly. |
| Identifying Magnetism |
| #1 |
Name three materials that are not magnetic. |
wood, copper, plastic, rubber, gold, glass, etc. |
| #2 |
How do you make a magnet? |
take an iron wire and stroke it with a magnet |
| #3 |
What is the difference in the way the atoms are arranged between magnetic and non-magnetic items? |
In magnetic items, the magnetic fields of the atoms line up. In nonmagnetized material, the magnetic fields of atoms do not line up. |
| #4 |
Name two ways to 'demagnetize' a magnet. |
heat it or strike it with a hard blow |
| #5 |
Name two materials that can be made into magnets. |
iron, nickel, cobalt |
| The Relationship Between Magnetism and Electricity |
| #1 |
What is electromagnetism? |
the relationship between magnetism and electricity |
| #2 |
How is an electromagnet created? |
by passing a current through a wire wrapped around an iron core |
| #3 |
Is an electromagnet always magnetic? Explain. |
no, an electromagnet is only magnetic when an electric current is flowing. |
| #4 |
Name three things that require electromagnets to operate. |
speakers, earphones, telephones |
| #5 |
What is the difference between a motor and and engine? |
motors use magnetic force to change electrical energy into kinetic (mechanical) energy. Engines change chemical energy (fuel) into kinetic energy (mechanical) to operate an automobile. |
