Electric currents, magnetic fields

Agenda Bell work• Magnet activity• Notes: Electricity and

Magnetism

• Electromagnetic Induction

• Circuits and Power Quiz tomorrow

• Outline Chp. 14 pg 235-245• Review Questions 1-17

• Pick up and complete Crossword Puzzle

Electric Currents, Magnetic Fields

May 7, 2012

Objectives

1. Describe the magnetic field produced by a current-carrying wire

2. Give examples of how the field can be made stronger

We KNOW

Electric wire can be made to have a current

Magnet has a magnetic field surrounding it

Interaction An electric current produces a magnetic field Magnetic field makes up a pattern of circles

When the current is reversed the direction of the magnetic field is also reversed

If a current carrying wire is looped the magnetic field is intensified

More loops means greater magnetic field

Electromagnets

If a piece of iron is placed in a current-carrying coil of wire, the iron will become a magnet – electromagnet (temporary magnet)

Roller coasters Junk yards Electric trains

Magnetic Forces on Wires

If an electric current can produce a magnetic field

Then, we can use a magnetic field to change an electric current

We can use the combination of both to create a motor