Transcript magnetism powerpoint

Why do they use magnets in Power Plants?
JOURNAL - Magnetism
• Draw a bar magnet
– Label the poles
– Draw what the field lines would look like
• How does the magnet in a power plant work? What does it do?
Magnetism: Magnetic Force
• Where is the magnet in the Power Plant? How does it work?
Magnetism: Magnetic Force
• Magnetic Force: The force a magnet exerts on another magnet,
iron, or moving charges.
Magnetism: Magnetic Force
• The force a magnet exerts on another magnet, iron, or moving
charges.
• Magnetic forces attract and repel one another
• Like = repel
• Unlike = attract
Why does this happen?
From where does this force come?
Magnetism: Magnetic Field
• Magnetic force comes from the magnetic field that surrounds a
magnet.
– Strongest at the poles where field lines are CLOSE, weak where
lines are FAR APART
N
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Magnetism: Magnetic Field
• A magnetic Field exerts a force on other fields.
Like poles repel because
Field lines push on each other.
Unlike poles attract because field lines
come together.
Magnetism
• What makes something magnetic?
• The spin of its UNPAIRED ELECTRONS. Electron spin aligns atoms and
creates a magnetic field.
Magnetism
• A material that has all of its atoms aligned in a single DOMAIN is
magnetic. Which one below is magnetic?
• Unaligned atoms
• Aligned atoms.
• MAGNETIC!
Magnetism: Earths Magnetic Field
The Earth also has a magnetic field, the MAGNETOSPHERE, due to its
iron core.
– Allows compasses to work
– Protects us from cosmic radiation
Magnetism: Electromagnetic Force
• Electromagnetic Force: the forces of magnetism and electricity
are both caused by electric charges.
– MAGNETISM – electrons spinning
– ELECTRICITY – electrons traveling
Magnetism: Electromagnetic Force
• In the same way that spinning electrons create a magnetic field,
traveling electric charges also create a magnetic field.
(see page 636)
Magnetism: Electromagnetic Force
• How is this useful?
• USES:
Solenoid: a coil of currentcarrying wire. The more
turns, the stronger the magnet.
It creates a controlled
magnetic field useful for many
things.
Magnetism: Electromagnetic Force
• USES:
Electromagnet: a coil of current-carrying wire with an iron core.
The more turns, the stronger the magnet. Used in junkyards to
lift heavy materials.
Magnetism: Electromagnetic Force
• USES:
Turbine Generator – a device that induces (creates) an electrical
current by spinning a magnet inside a coil of wire or vice versa.
Magnetism: Electromagnetic Force
• USES:
Turbine Generator – a device that creates an electrical current by
spinning a magnet inside a coil of wire or vice versa. Used at
electrical power plants to create electricity.
Magnetism: Electromagnetic Force
• USES:
Turbine Generator – a device that creates an electrical current by
spinning a magnet inside a coil of wire or vice versa. Used at
electrical power plants to create electricity.
Magnetism: Electromagnetic Force
• USES:
Transformer – a device that increases or decreases voltage and
current. Used when electricity is being transported to your
home for use.
Magnetism: Electromagnetic Force
• USES:
Transformer – a device that increases or decreases voltage and
current. Which one increases? Decreases?