4 th grade Physical Science Part 2

1. 4th grade Physical Science Part 2 L.O. I will describe how magnets and electromagnets work.

2. DAY 1

3. Magnets will attract certain metals • Permanent magnet – an object that keeps magnetism for a long time • Temporary magnet – will lose magnetism after a short time • *Magnetic Poles – areas where the force of the magnet is greatest

5. *Bar and horseshoe magnets – pole is at the ends • Ring magnet – pole is on the face

6. *A compass is a free floating magnet that will always point North • *Like poles REPEL – push away • *Opposite poles ATTRACT – pull together S N N

7. Magnetic Earth • Earth’s center is made up mostly of molten iron • As Earth spins, the iron particles line up, producing Earth’s magnetic field • *So Earth is like a gigantic bar magnet • *It is surrounded by a magnetic field with lines of force

8. Day 2

9. *Electricity can produce magnetic fields • This is called an electromagnet • When the electric current passes through the wire, the current produces a weak magnetic field around the wire Iron nail wire Power source switch

10. *To make the electromagnet stronger you can • *wrap more wire around the iron nail • *use more batteries or bigger batteries • If I take the batteries out or turn the switch off, the nail loses it magnetism

11. *Electrically charged objects will become a magnet and will either attract or repel • A motor will make a fan move • *An electric motor changes electrical energy into energy of motion • They use electromagnets and permanent magnets by using like poles to repel and the opposite poles to attract, making the motor move • *Electrical energy will convert to light, heat, and motion