The Science of Electricity

By: Nicole Hayes

What is Electricity?

• Electricity is a form of energy that starts with atoms.

All About Atoms• Atoms are tiny particles that make up everything

around us.• Atoms have 3 basic parts:– Protons

• Inside the nucleus.• + charged

– Neutrons• Inside the nucleus• No charge

– Electrons• In rings around the nucleus.• - charged

– Atoms have the same number of protons and electrons.

Diagram of an Atom

Electron Movement

• Electricity can be created by forcing electrons to flow from atom to atom.

The Periodic Table

• A chart which organizes the elements.– Made by Dimitri Mendelev in 1869.– Atoms are arranged by increasing atomic number

(number of protons in nucleus).– Vertical columns are called groups.– Horizontal rows are called periods.– Placement of element on table indicates ability to

produce electricity.

Happy Atoms

• Atoms are the happiest when their outer shell has 8 electrons.

• Atoms will tend to bond with those who can make them “happy”.

• Those who have fewer electrons will share them with another who has more.

• This flowing of electrons by “donors” make them good conductors.

Conductors

• Elements that allow electrons to flow easily through it. (Electricity flows).

• Determined by number of valence (outer shell) electrons.

• Conductors have 3 or fewer valence electrons.

Insulator

• An element that does not allow electrons to move freely within it.

• Elements with a full set of valence electrons.

Semi-Conductors

• An element that is neither a conductor nor a good insulator.

• Allows some current to flow, but offers a lot of resistance.

• Found in transistors, integrated circuits, and solar cells.

• Outer shell has exactly 4 electrons.

Current vs. Static Electricity

• Electricity that is moving.

• Ex: Copper wire moving electricity from a power plant to a house.

• Electricity that is standing still.

• Ex: Getting a shock after walking across carpet and touching something.

How is Electricity Produced

• Various energy sources are used to turn turbines.

• The spinning turbine shaft turns electromagnets which are surrounded by heavy coils of copper wire inside generators.

• This creates a magnetic field which allows the electrons in copper wire to pass freely from one atom to another.

Turbines

Sending Electricity Out From the Plant

• Electricity is sent down transmission lines from the plant.

• Electricity loses some of its voltage (strength) as it travels.

• Transformers help boost up its power.• When the electricity gets where it needs to go,

the voltage must be stepped down before being used. This is done at sub-stations.

• The electricity is then carried on distribution lines throughout neighborhoods to houses.

• It is stepped down one more time before entering the house.

• It enters the house through wires passing through a meter box.

• When you flip a switch, you complete a circuit. • This allows electricity to pass through the

appliance, back down the cord, and back into the electrical line.

Electrical Terms

• Voltage- the “pressure” under which electricity flows.– Like turning on the faucet for the flow of water.

• Amperage- measures the amount of electrical current.– Measuring the amount of water moving through the hose.

• Watts- measures the amount of work done by a certain amount of current at a certain pressure.– Washing a muddy car off would require much more water

at a higher pressure.

Formulas

• _____P_____ I E

Where P is power (watts), I is current (amps), E is voltage.

• So, watts = amps x volts• Watts/current = voltage• Watts/voltage= current