Bell Ringer: You need a calculator, ipad, book & periodic/reference table! 1) Which way do electrons flow in a circuit? 2) Do like charges attract or repel each other? 3) Name two types of forces that we have talked about in this class, and describe them. Quick Math Review: Put these numbers in scientific notation: 14,340,000.00 .0000867 Put these numbers in standard notation: 1.23 x 104 7.8 x 10-3

Magnetism Chapter 21

Magnets Magnetism Force of attraction/repulsion between two objects. 2 sides to every magnet: North (N) Points magnetic north South (S) Points magnetic south end

Magnets Magnetic Forces Opposites Attract Closer to the Pole = Stronger Force Area it acts on objects is called the Magnetic Field end

Magnets Field Lines show the area affected by the Magnetic Field Arrows go from North to South More Lines = Stronger Field When 2 Magnets come close together the Field Lines interact with each other! end

Magnets Field Lines interact between 2 magnets Attraction end

Magnets Repulsion end

Magnets Magnetic Domain Area where atoms have the same magnetic charge Point in the same direction Create a magnet using Magnetic Induction Force all Domains to point in the same direction end

Magnets Magnets can be either: Temporary Permanent Easily magnetized but loses strength quickly. Permanent Hard to magnetize but keeps strength a long time. Common Magnetic Elements cobalt, nickel, iron, aluminum end

Electromagnets As Electricity runs through a coiled wire it creates a Magnetic Field Magnetic Field lines look the same as Field Lines Known as an Electromagnet end

Electromagnets Electromagnets all us to use electricity to create magnets of strength & to make objects attract end

Electromagnets 3 parts: 1. Power Source 2. Wire 3. The Core Wire wrapped around the core Core 3 parts: 1. Power Source Need to be able to change the Current in the circuit 2. Wire 3. The Core end

Electromagnets To increase the strength of an electromagnet: Increase the current Increasing the number of turns in the wire Wrap the wire more times around the core Use a core that is easily magnetized end