Transcript Ch 6, Lesson 3 and 4 ppt - Effingham County Schools

Chapter 6
Chapter 6
Lesson 3
http://www.youtube.com/watch?v=ak8Bh9Zka50
Magnet:
an object that attracts certain metals, mainly iron
The property of magnets to attract metal is called
magnetism
• Magnets do not attract all metals. They don’t attract
materials such as wood or rubber.
• Magnetism is a force. The space in which a magnet’s
force can act is called its magnetic field.
• Each magnet has two magnetic poles where the
magnet’s force is the greatest.
Magnetic Poles: the 2 areas on a magnet with the
greatest magnetic force
• When a bar magnet can swing freely, one end
always points North.
like – repels
unlike - attracts
magnetic poles
The Earth as a magnet
The center of the Earth is made up mostly of melted
iron. As Earth spins, the iron particles line up.
Imagine Earth with a giant bar magnet inside. This
means that Earth has a magnetic force field around it.
The needle of a magnetic compass is a permanent
magnet. The needle can always turn freely. One end of
a compass needle always turns to find north.
Who is a compass helpful for? sailors
www.brainpopjr.com/science/forces/magnets/
Chapter 6 Lesson 4
http://www.brainpop.com/technology/energytechnology/electromagnets/
Magnetism and electricity can produce energy of
motion.
Electromagnet: a strong temporary magnet that uses
electricity to produce magnetism
Examples:
• blender
• doorbell
Motor: a device that changes electrical energy into
energy of motion
Generator: a device that uses magnetism to convert
energy of motion into electrical energy.
Uses energy all the time:
fridge
clock
DVD player
computer
Uses energy some of
the time:
fan
washing machine
Essential Question:
How is an electromagnet different from a bar magnet?
1) Magnetic force can be controlled.
2) can be turned on and off
Study Guide
1.An conductor is a material that electric charges can flow
through easily.
2.The pathway that an electric current follows is called
a(n) electric circuit.
3.The force of a magnet is strongest at the magnetic
poles.
4.A motor is a device that uses magnetism to convert
electrical energy into energy of motion. (mechanical)
5.An electric cell is a device that changes chemical energy
into electrical energy.
6.Objects with unlike electric charges attract. Like items
repel.
7.Static electricity is built-up electric charge.
8. Open circuit: gap, or opening, in a circuit
9. Closed circuit: connect wire, battery, & bulb without
gaps
10. Series circuit: current passes each part in a single
pathway
11. Parallel circuit: current passes in >1 pathway
12. Name 3 conductors: copper, silver, water, living
things
13. Name 2 insulators: plastic, rubber
14. In a string of lights, all of the lights do not work if one
bulb is removed . This is a series circuit.
What is static electricity?
What causes static electricity to discharge?
Static electricity is a build-up of negative electric
charges. This build-up will remain until these negative
charges jump from a charged object to another object.
This “jump” creates the shock you feel.
You rub a balloon with a wool cloth, and touch it to
the wall. The balloon sticks. What can you conclude
about the electric charges on the balloon and on the
wall?
The balloon receives negative charges from the
wool cloth. The wall is neutral object that contains
positive charges. These unlike items attract.