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CHAPTER 3 SECTION 1
What Is Electromagnetism?
SPONGEBOB LAWYERPANTS YOUR HONOR
OBJECTIVES
• N.3.1.1. Explain how electric current is
related to magnetic fields.
• N.3.1.2. Identify some characteristics of a
magnetic field produced by an electric
current.
• N.3.1.3. Describe the characteristics of an
electromagnet.
I CAN DO THIS EASY STUFF
ELECTRIC CURRENT AND MAGNETISM
• An electric current produces a magnetic
field. Objective N.3.1.1.
• Whenever electricity flows through a wire, the
moving electrons (electric charges) produce a
magnetic field around the wire.
SOLENOIDS
• The magnetic field produced by an electric
current has three distinctive features:
Objective N.3.1.2.
• 1) It can be turned on and off.
• 2) Its direction can be reversed.
• 3) Its strength can be adjusted.
SOLENOIDS
• A coil of wire with a current
in it is called a solenoid and
the ends of the solenoid act
like poles in a bar magnet.
The magnetic field around
a solenoid is the same as a
magnetic field around a bar
magnet with the two poles:
• North Pole
• South Pole
SOLENOIDS
Solenoid
Bar Magnet
ELECTROMAGNETS
• When you put a ferromagnetic
material inside a solenoid and
pass electric current through
the wire, you make an
electromagnet. What is the
biggest advantage to an
electromagnet vs. a regular
one?
• They can be turned on and
off. Objective N.3.1.3.
ELECTROMAGNETS
• Electromagnets
are often used in
junkyards to
separate iron from
other materials.
ELECTROMAGNETS
• Can anyone think of
how they might be used
in the food industry?
• They are often used to
remove metals from the
food stream or to check
foods for metals to
protect your health.
ASSESSMENT
ASSESSMENT
• 1a. Who discovered that electricity and magnetism are
related?
• Hans Christian Oersted
• 1b. What is the relationship between electric current and
magnetism?
• An electric current in a wire creates a magnetic field around it.
• 1c. How can a magnetic field be produced around a wire?
• By putting current through the wire.
ASSESSMENT
• 2a. What is a solenoid?
• A solenoid is a coil of wire that mimics a bar magnet
when a current is passed through it.
• 2b. What are three characteristics of a magnetic
field produced by a current?
• They can be turned on and off.
• The magnetic field can be reversed.
• The strength of the magnet can be adjusted.
ASSESSMENT
• 2c. How could you increase the strength of a solenoid?
• Add more turns of wire.
• Add an iron core to it.
• Increase the current in the wire.
• 3a. What makes an electromagnet stronger than a
solenoid?
• An electromagnet has an iron core inside the solenoid.
ASSESSMENT
• 3b. What are the four ways to make an
electromagnet stronger?
• Increase the current in the coil.
• Add more turns of wire to the solenoid.
• Make the loops in the solenoid smaller or tighter.
• Add a stronger ferromagnetic material to the core.
I TOLD YOU I COULD DO THIS