Magnetism&

ElectromagnetismDrill: What happens to the forces

between magnets as they get closer together?

Objective: SWBAT demonstrate mastery of magnetism and electromagnetism concepts

successfully through discussion and completion of a pre quiz.

Magnet Review• This magnetic field is invisible but is responsible

for the force that pulls on other magnetic materials and attracts or repels other magnets.

• Permanent Magnet– The object is made of magnetized material– Materials that can be magnetized, which are

also the ones that are strongly attracted to a magnet, are called ferromagnetic. These include iron, nickel, and cobalt.

3-D Magnetic Field Lines

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Magnetic Field Lines

• Where the lines get closer, which is at the ends, the force becomes stronger.

• If we want to pick up a magnetic material, we would test it on the ends of the bar magnet.

Forces Between Magnets

• Opposites attract (N & S or S & N) and likes repel (N & N or S & S)

• As we bring two magnets together, the force of either repelling (like poles) or attraction (opposite poles) becomes stronger.

• If two poles are far away, you can barely feel a force.

Breaking a Magnet

• When we break a magnet, the outside poles stay the same. But you cannot just have one pole of a magnet, so the insides have to take on the other pole

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Electromagnet

• When a current flows through a wire it produces a magnetic field.

• The magnetic field around a straight wire is circular.

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Ways to Increase The Strength of an Electromagnet

• Use a soft iron core.

• Use more coils (more loops around)

• Add more current (bigger battery)

Electricity Vs. Magnetism

• Both – Opposites attract (N & S and + & -)– Both deal with electrons of the atom– Both need conductors to work– Electricity can make a magnet

(electromagnet) and magnetism can make electricity (generator)

Homework

• Finish PreQuiz