Magnetic Forces

1. Magnetic Forces

2. In this activity you will: • Learn about magnetism and electricity. • Write a paragraph using three facts about magnetism and three facts about electricity.

3. What is magnetism? • Magnetism is the force of attraction between magnets and magnetic objects.

4. Characteristics of magnets • Every magnet has two poles (North and South) • Every magnet has a magnetic field around it. • The magnetic field is lines of force running from the north-seeking pole to the south-seeking pole of the magnet

5. What do you know of that has a North and South Pole? • If you answered The Earth you were right! • The Earth is one giant magnet. It has two magnetic poles and is surrounded by a magnetic field. • This magnetic field is what causes the needle of a compass to point in different directions and causes the poles of a magnet to point either north or south.

6. Do opposites attract? • Yes! • The north and south seeking poles of two magnets attract each other- magnetic force pulls them together. • But if you try to bring two of the same poles (two norths or two souths) together they will repel each other.

7. Magnets and electricity • Magnets are used to generate, or produce, electricity. • Spinning a coil of wire inside a magnetic field produces an electric force between the ends of the coil. • In a similar way, an electric current produces a magnetic field around it.

8. Electromagnet • A temporary magnet made by passing electric current through a wire coiled around an iron bar. • A junkyard is one place to see an electromagnet in action. A crane holding a huge electromagnet can be used to pick up scrap metal when current flows through it. When the crane operator wants to drop the scrap, he or she will simply shut off the current to the electromagnet.

9. Ten Facts about Magnets • 1. North poles point north, south poles point south. • 2. Like poles repel, unlike poles attract. • 3. Magnetic forces attract only magnetic materials. • 4. Magnetic forces act at a distance. • 5. While magnetized, temporary magnets act like permanent magnets.

10. 6. A coil of wire with an electric current flowing through it becomes a magnet. • 7. Putting iron inside a current-carrying coil increases the strength of the electromagnet. • 8. A changing magnetic field induces an electric current in a conductor. • 9. A charged particle experiences no magnetic force when moving parallel to a magnetic field, but when it is moving perpendicular to the field it experiences a force perpendicular to both the field and the direction of motion.

11. 10. A current-carrying wire in a perpendicular magnetic field experiences a force in a direction perpendicular to both the wire and the field

12. Writing Activity • Write a paragraph about magnetism and electricity including three facts about each that you learned during this presentation.