The Earth, Electricity, & Magnets

1. The Earth, Electricity, & Magnets

2. The Earth as a Magnet • The Earth is actually a big magnet. The Earth’s magnetic field is called the magnetosphere. • Earth’s magnetic North and South poles are actually not the same as the geographic poles. The difference between the two is called the magnetic declination. • Theory is that the Earth’s core is what generates this field

3. Earth’s Magnetic Field • This magnetic field around Earth protects us from charged particles the sun produces that could harm us. • ~700,000 ago years the north and south magnetic poles switched on the planet. • Evidences is shown in our rock record.

4. Electromagnets • Magnetic fields are produced by moving electric charges, the electrons moving around the nucleus of an atom. • You can create a magnet by using coiled wire, a voltage source and a magnetic material. • Electromagnet: is a current-carrying wire wrapped around an iron core.

5. More Electromagnets • The magnetic field of an electromagnet is turned off when the electric current stops. • If you change the direction of the current you can change the strength and direction of the magnetic field. • This is used for electric motors! • And doorbells

6. Uses for Electromagnets • Generators use magnetic fields to turn motion into electricity. • Generators: kinetic energy is changed into electric energy • Motors: electric energy is changed into kinetic energy. • Both of these use can use magnets

7. Superconductors • When most conductors of electricity have a current flowing through them they heat up. • Some objects that are cooled to very cold temperatures become superconductors which have no resistance to electric flow. • They produces a magnetic field opposite to that of regular magnets and will repel them.

8. Note Quiz • What is a benefit about having a magnetic field around Earth? • Define Electromagnet. • The difference between the geographic north pole and the magnetic north pole is called?