ELECTROMAGNETISM

1 / 69

# ELECTROMAGNETISM - PowerPoint PPT Presentation

ELECTROMAGNETISM. Bell Work. Welcome back, I hope you had a great break! (Write each statement then decide if it is true or false, if false correct) The basic particles of an atom are protons, neutrons, and nuclei. Particles that make up an atom have no charge.

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.

## PowerPoint Slideshow about 'ELECTROMAGNETISM' - cale

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

### ELECTROMAGNETISM

Bell Work

Welcome back, I hope you had a great break!

(Write each statement then decide if it is true or false, if false correct)

• The basic particles of an atom are protons, neutrons, and nuclei.
• Particles that make up an atom have no charge.
• Electrons are negatively charged.

Unlike charges

attract.

Like charges repel.

Electricity 1.1 Vocab
• Electric charge – a property that allows an object to exert an electric force on another object without touching it.
1.1 Vocab Cont.
• Electric field – the space around a particle through which an electric charge can exert force

At first, a balloon and a glass rod

each have balanced, neutral charges.

1.1 Vocab Cont.
• Static charge – a buildup of electric charge in an object caused by the presence of many particles with the same charge

Afterwards, the balloon has a negative charge, and the rod has a positive charge.

At first, a balloon and a glass rod

each have balanced, neutral charges.

When they touch, electrons move from the rod to the balloon.

1.1 Vocab Cont.
• Induction – the buildup of a charge without direct contact
Bell Work

Draw a picture and explain each answer.

1. How do two positive particles interact?

2. How do two negative particles interact?

3. How do a positive and a negative particle interact?

Bell Work

• A sock and a shirt from the dryer stick together. What does this tell you about the charges on the sock and shirt?

2. You walk over a rug and get a shock from a doorknob. What do the materials of the rug and the shoes have to do with the type of charge your body had?

Choose one of the following to complete

• Make a PowerPoint for the vocab words on page 18. Each word should have 2 slides. First slide: word, definition, and a sentence in your own words. Second slide: word and a picture.
• Make a 4 square chart 

For each of the vocab

words on page 18.

1.2 Vocab

Electric potential – the amount of electric potential energy per unit charge at a certain position in an electric field.

Volt – equal to one joule of energy per coulomb of charge

Conductor – a material that allows an electric charge to pass through it easily

Insulator – a material that does not easily allow a charge to pass through it.

Resistance – the property of a material that determines how easily a charge can move through it

Ohms – the unit for measuring electrical resistance

Bell Work 5/12/11

Draw a picture and explain what happens when there is lightning. (hint look at pg 25)

Bell Work 5/11/11

Bell Work 5/12/11

Make a chart with at least 5 conductors and 5 insulators in it.

Bell Work 5/13/11
• What is electric potential?
• What 3 factors affect how much electrical resistance an object has?
• How can a lightning rod protect a building from fire?
Bell Work 5/16/11
• Why do lightning rods work better if they are placed high up, closer to the lightning charge?
• Could the same material be used as both a conductor and an insulator? Explain your answer.
Bell Work 5/17/11
• Draw a picture of a wire with low resistance.
• Draw a picture of a wire with high resistance.
• What might wire made with low resistance be used in?
• What might wire with high electrical resistance be used in?
Bell Work
• How much resistance does a superconducting material have? (pg 24)
• What is a ground cable? (pg 25)
1.3 Notes

Electric Current – the flow of charge (+,-) through a material.

Electric currents produce magnetic fields --- spinning/moving electrons.

1. circuit has a source of electrical energy.

2. circuits have devices that are run by electrical energy.

3. electric circuits are connected by conducing wires and a switch.

Ampere – the standard unit of measure for current

Ohm’s law – shows relationship between current, voltage, and resistance

Current = Voltage I = V

Resistance R

Electric cell – produces electric current using the chemical or physical properties of different materials
Primary cell – produce electric current through chemical reactions until the chemicals are all used up

Storage cell – produce electric current through chemical reactions that can be reversed in the battery

Bell Work 5/19/11

Make a Venn diagram comparing and contrasting electric current and static discharge.

Bell Work 5/24/10

Good morning. Please get out your study guide and begin reviewing for the final.

Bell Work
• Where do solar cells get their energy?
• What kind of battery can be charged by reversing chemical reactions?
• What does an ohmmeter measure?
• In which direction do electrons flow when a storage cell is being charged?
Bell Work 5/25/11
• An electrical pathway has a voltage of 240 volts and a current of 10 amperes. What is the resistance?
• A 240-volt air conditioner has a resistance of 8 ohms. What is the current?
• An electrical pathway has a current of 1.2 amperes and resistance of 40 ohms. What is the voltage?
Bell Work

Write a paragraph about your favorite part of science class this year and your least favorite part of science class this year

- Then get out your study guide and review

Magnetism – The attraction of a magnet for another object.

Magnetic pole – end of a magnet, a pole is the area of a magnet where the magnetic effect is strongest. Pg 18

alike poles repel and opposites poles attract each other.

Magnetic Fields - the region of magnetic force around a magnet.

Inside a Magnet

Atom – smallest particle of an element that has the properties of that element.

Element – Is on of about 100 basic materials that make up all matter.

Nucleus – Center of an atom that contains the PROTON and the NEUTRON.

Proton – the positive charged particle of an atom.

Neutron – Contain mass only (NO CHARGE).

Electron – Very small particle Found circling the nucleus with a negative charge.

Magnetic domain – when a large portion of the atoms in a material are lined up in the same way.

In a magnetized material all or most of the domains are arranged in the same direction.

Iron is a substance that will undergo magnetism because the domains can be aligned to have a strong magnet.

Temporary magnets – when domains are alligned for a short period of time. Like placing a magnet on a group of paper clips
Permanent magnet – A magnet made of a material that keeps its magnetism. The more iron in the magnet the better (stronger) the magnet.

Earth as a Magnet

Although not completely understood the popular theory is --- the molten iron and nickel core is spinning causing the generation of a magnetic field around Earth.

Earth has both a North and South magnet pole, just as a bar magnet does.

Magnetic Declination – the angle between geographic north (true north) and the north to which a compass needle points.
• Magnetic north is 1250 km (776 miles) from geographic north.
• Magnetosphere -
The Earth will actually make iron object magnetized over a long period of time, if the object doesn’t move.

The rock that forms from lava will have a magnetic domain facing the poles of the Earth. Over 800,000 year the magnet poles of the Earth will swap. Don't know why, but da do!!!

Electric currents produce magnetic fields --- spinning/moving electrons.

Circuit – complete path through which electric charges can flow.

1. circuit has a source of electrical energy.

2. circuits have devices that are run by electrical energy.

3. electric circuits are connected by conducing wires and a switch.

Resistance – the opposition to the movement of charges flowing through a material.

Superconductors – materials that have no resistance to electrical flow. NO LOSS OF ENERGY occurs in a superconductor.

Solenoid – a current carrying coil of wire with many loops.

Electromagnet – a solenoid with a ferromagnetic core. Can be turned off and on.

Resistor: A resistor uses electrical energy or “resists” the flow of charge in an electrical circuit.

Light bulb, any electrical appliance.

Electricity
• The unit of current is the ampere or “amp”.
• It tells the amount of charge flowing past a point at any given second.
• ALL MAGNETISM IS CAUSED BY MOVEMENT OF CHARGES.

http://www.pbs.org/wgbh/amex/edison/sfeature/acdc.html

Conductors: Electrons are loosely bound to the atom and electrical currents move freely through the wire.
• Copper, aluminum, silver and iron.
• Insulators: Electrons are bound tightly to atom and do not flow easily.
• Rubber, glass, plastic, sand, wood.
Static Electricity: Charges build up, but do not flow.

Caused by:

• Friction-transfer of electrons from one object to another by rubbing.
• Ex: clothes in a dryer
Conduction: the transfer of electrons by direct contact.

Ex: touching a car door or someone and getting shocked!

Induction: the movement of electrons to one part of an object caused by the electric field of another object.

Voltage: The force that pushes the electrical charge through the wire.

Series Circuit: Only one path for the current to take.
• Pro: Simple and cheap to make
• Cons: 1. If one light goes out, they all do
• Lights become dimmer as you add more bulbs (less current and more resistance!)
Parallel Circuit: Several paths for the current to take.
• Pro: Individual bulbs can be turned on and off without affecting each other. Ex:
• Household circuits
A scientist is experimenting with bacteria that are one micron in diameter and that reproduce by dividing every minute into two bacteria. At 12:00 PM, she puts a single organism in a container. At precisely 1:00 PM, the container is full.
• At what time was the container half full?

2.There are twelve identical-looking balls, but one is either heavier or lighter than the other eleven. How can you determine which is the odd ball and find out whether this ball is heavier or lighter than the others using only three weighings with a balance?

Bell Work
• What is going to be the most difficult part about building your box?
• What is going to be the easiest part about building your box?
Bell Work

If you could make 3 changes to your box what would they be? Please write a paragraph to answer the question.