826 Distinguish among the Earth’s magnetic field, a magnet, and the fields that surround a magnet and an electromagnet.

I.Magnetic Fields A.Magnetic field – the area surrounding a magnetic object in which the magnetic force exists B. The Earth’s Magnetic Field 1.The earth behaves as if it has a bar magnet running through it. 2.The North and South poles of the magnet are near the Earth’s North and South poles of the Earth 3.Although the magnetic field is strongest near the poles the Earth’s magnetic field does surround the entire planet 4.The Earth’s magnetic field traps and deflects particles from the sun that might otherwise be harmful to life. 5.The Earth’s magnetic field has reversed several times in the past!

C. A Bar Magnet 1.Because of the way the domains (groups of charges) are aligned, a bar magnet has a north and south pole just like the earth 2.The field is strongest at the poles but surrounds the entire magnet 3.The magnetic field of a bar magnet is constant

D. An Electromagnet 1.An electromagnet is a wire with coils (a solenoid) that has an electric current running through it and an iron core inside the coil. 2. Adding coils to the wire, adding more current, and adding an iron core greatly increases the magnetic field. 3. The magnetic field of an electromagnet has North and South poles that center around each end of the iron core. 4. Not constant but varies with current strength, number of coils, and size of the iron core.