Bellringer

1) What do you know about electrons?

2) What do you think causes lightning?

Agenda

NOTES: ElectricityStatic ChargesElectric FlowInsulators & ConductorsDesign of Electric Wires

Definition of Electricity

Electricity is the movement of electrons.

Electrons are very tiny, negatively charged particles that are found in every object.

Charge

Since electrons are negative, they change the charge of objects when they move.

When an object gains electrons it becomes negatively charged.

When an object loses electrons it becomes positively charged.

http://www.youtube.com/watch?v=mtY3M-mwdZY

Charged Objects Push & Pull

Charged objects can push and pull each other, kinda like magnets.Opposite charges attract each otherSame charges repel each other

Direction of Electric Flow

Electricity ALWAYS flows away from Negative charges or towards Positive charges.

This is why batteries are labeled with + and – signs. Electricity comes out of the negative end and returns to the positive end.

Example 1: Lightning

During Lighting, electrons flow away from the negatively charged clouds towards the ground

Example 2: Balloon Stuck on Wall

http://phet.colorado.edu/en/simulation/balloons

Conductors and Insulators

Some materials allow electrons to flow through them very easily, while others do not allow electrons to flow.

Materials that allow electricity to pass through them are called conductors. All metals are conductors.

Materials that do not allow electricity to pass through them are called insulators. Rubber and Wood are insulators.

Design of Electrical Cords

Electrical cords contain conductors and insulators.

There is copper inside the wire to carry electricity, and a rubber coating to prevent getting shocked.

Grounding Wire

The “Third Prong” of an electric cord does not carry electricity. It carries overloads into the ground in order to prevent shocking people.

How Tasers Work

Brain uses electricity to tell your muscles to move.

A stun gun forces all of your muscles to squeeze.

There is a small risk for people with weak hearts.

Assignments

11 Review Questions