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Electricity & Magnetism Lessons

5th Grade Strand 5: Physical Science

StandardsConcept 3: Energy and Magnetism

Presents:

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Electricity Basics

Electricity is…..

• The flow of electrons • The energy sent out by batteries and

generators (current electricity)• The shock you can get from rubbing

your feet on the carpet (static electricity)

• A bolt of lightning! (static electricity)

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All Matter is Made up of Atoms

MATTER(Diamond, coal)

ELEMENT(Carbon, Oxygen)

ATOM(particles)

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Atoms

What is an Atom?The smallest component in all thingsMade up of three smaller particles

Protons (+) Neutrons (no charge)Electrons (-)

Strive for stabilityCharged atom = ion

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Opposites Attract

Particles with opposite charges attract each other.

Attraction

+ _+ _

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Charged Atom (Ion)

Stable atoms have equal protons and electronStable atoms have no charge Free electrons will seek positively charged ions

to create stability

Stable Atom+++

--- Positive Ion

+++

-- Negative Ion

++

---

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Static Electricity

The imbalance of positive and negative charges

Example: a build up of negative charges in a storm cloud will travel to the ground in the form of lightening

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Static ElectricityStart with a doorknob – no chargeWalk along carpet: strip electrons from carpet that

collect in your body… You become negatively charged

Approach the doorknob and the positive charges move toward you. Negative charges move away.

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Static ElectricityWhen close enough, the electrons will jump toward the

positive doorknob and ZAP! You’ve been shocked by static electricity.

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Static ElectricityWhen close enough, the electrons will jump toward the

positive doorknob and ZAP! You’ve been shocked by static electricity.

Now you and the doorknob have the same charge.

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Electricity & Ben Franklin

Benjamin Franklin (1706-1790)1740’s – Proposed the notion

of positive and negative charges maintain a balance except when influenced by some means.

1752 – Famous kite experiments identify lightning as a form of electrical discharge.

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Current Electricity

Electric current is the movement of free electrons from atom to atom

To start the free electrons moving an electromotive force is needed. Generator Batteries

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Voltage and Current

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What is an Atom?

The smallest component in all thingsMade up of three smaller particles

Protons (+) Neutrons (no charge)Electrons (-)

Free electrons search for positively charged ionsThe flow of electrons is electric current

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Voltage & Current

VoltageElectric potential difference between two points Pushes electronsMeasured in VoltsComes from batteries, electric outlets,

generatorsCurrent

Flow of electronsMeasured in Amps1 amp = 6,240,000,000,000,000 electrons

moving past a point every second

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Voltage is like Pressure

Higher voltage pushes electrons to move faster (higher current)

Higher pressure pushes water to flow faster

You can have pressure without flow

You can have voltage without current

Pre

ssu

re

Pre

ssu

re

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Current is like water flow

Flow of water is similar to flow of electrons

The pressure (voltage) determines how fast the water (electrons) move through the pipe (wire)

There is no current without voltage F

low

Flo

w

How Do You Get Electricity?

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Conductors and Insulators

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Conductors

Materials that pass electricity easilyExamples:

CopperSilverGoldAluminumMost metals

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Insulators

Materials that resist electricity flowExamples:

WoodRubberPorcelainGlassAirClothPaper

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Electricity & Thomas Edison

Thomas Edison (1847-1931)1870’s – invented the first

commercially practical incandescent light with a carbon filament.

1880 – Edison founded the Edison Electric Illuminating Company the first electric utility in New York City.

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Circuits:Series and Parallel

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What is a circuit?

A circuit is a conductor path for electric current to travel through.

Current will flow only if the path is a complete loop from negative to positive

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What makes a simple circuit?

A simple circuit consists of:1. A source - battery or generator

2. Conductors (path for current to flow)

3. An electric resistor or electric load - light bulb or an electromagnet

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Series CircuitIn Thomas Edison’s day, most lights were

connected in series (one after another)Christmas tree lights are sometimes

connected in seriesWhat happens if we add another light bulb?

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Series Circuit – Adding bulbs

Do the bulbs get brighter or dimmer?Why would they change?What if we add a million light bulbs?

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Parallel Circuit

By making a loop for each bulb we can make a parallel circuit

What are the benefits? What happens if we add another bulb?

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Parallel Circuit – Adding bulbs

Will the brightness of the bulbs change?Why or why not? What if we add a million bulbs?

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Questions to Ponder

What would life be like without electricity?

Are the electrical outlets in your house installed in series or parallel?

Can you think of an example of a series circuit in real life?

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What is Magnetism?

Any material that attracts ferromagnetic materials including iron, steel, cobalt and nickel

Can be permanent or temporary

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Magnetism Basics

SN

Magnets can be made in a variety of shapes, but all magnets have 2 poles

•Opposite poles attract•Like poles repel

All magnets have lines of force extending from one pole to the other in the 3 dimensional space around them

Only Certain Types of Materials Exhibit Magnetism

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Magnetic Lines of Flux

N magnet S

Magnetic Field

Magnetic lines do not crosseach other.

The lines go from Northto South on the magnet.

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Magnets Attracting Each Other

Pulling

N SN S

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Magnets Opposing Each Other

N S

N S

Pushing Apart

The Earth is a Magnet

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What are the characteristics?

North and south poles“di”-polesBreak the magnet in half and you will have two

separate magnets

3 dimensional field of attraction

Transfer magnetic properties

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Uses for Magnets in Everyday LifeCars

Power locks

HomesDoor bellsMicrowavesTV’sRefrigerators EarringsElectricity

SchoolsWhiteboard Magnets

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References

www.srpnet.com/educationwww.ieee.orghttp://teacher.scholastic.com/dirt/circuits/whatcirc.htm

www.en.wikipedia.org/wiki/Magnets www.creativekidsathome.com/science/

magnetexp.html

www.howstuffworks.com www.eia.doe.gov/kids/glossary