Magnets Quiz: Understanding Magnetism

Magnets

• Magnets are special stones that interact with some metals.
• Natural magnets, like magnetite (lodestone), attract iron.
• Man-made magnets are usually iron or steel and come in various shapes (U-shaped, horseshoe, bar, rod, ring, button).
• Magnets attract some materials (magnetic materials) such as iron, nickel, cobalt, and steel.
• Non-magnetic materials are not attracted to magnets, including gold, silver, aluminum, copper, wood, paper, plastic, glass, and clay.
• Objects like nails and paperclips are magnetic because they are made of iron.
• Steel is also a magnetic material.

Magnet Characteristics

• A magnet's force is strongest at its poles (North and South).
• Like poles (N-N or S-S) repel each other.
• Unlike poles (N-S) attract each other.
• The north pole of one magnet attracts the south pole of another.

Force and Effects

• Force is a push or pull applied to an object.
• Forces can cause objects to start moving, change speed or direction, change shape, or stop moving.
• Examples of force include pushing a car, pulling a trolley, squeezing a lemon, kicking a ball, etc.
• Friction is a force that slows or stops a moving object.

Magnet Uses

• Magnets are used in many electrical appliances (telephones, headphones, speakers).
• Small electromagnets are used in computers and video recorders for handling information.
• Magnets can keep refrigerator doors shut.

Electromagnets

• Electromagnets are temporary magnets.
• They work as magnets when electricity flows through them.