Warm-Up Exercises

Get a copy of the test and your scantron. Complete your Energy and

Machine Test Analysis.

S8P5. Students will recognize characteristics of gravity, electricity, and magnetism as major kinds of forces acting in nature.

b. Demonstrate the advantages and disadvantages of series and parallel circuits and how they transfer energy.

c. Investigate and explain that electric currents and magnets can exert force on each other.

Why do some clothes stick together when they come out of the dryer?

Key Ideas about Electricity

Standard for today’s lesson

S8P5Students will recognize characteristics of gravity, electricity, and magnetism as major kinds of forces acting in nature.

b. Demonstrate the advantages and disadvantages of series and parallel circuits and how they transfer energy.

c. Investigate and explain that electric currents and magnets can exert force on each other.

Essential Question

Why do some clothes stick when they come out of the dryer.

Electric charge is a property that allows an object to exert a force another object without touching it.

Electrons have a negative charge.

Protons have a positive charge.

Like charges will repel (push away) each other and unlike charges will attract (pull toward) one another

Electrons have a negative charge.

Protons have a positive charge.

the force (a push or a pull) on a charged object due to an electric field

Note: Like charges push Unlike charges pull

the space around a charged object in which another charged object experiences an electric force

Most objects have approximately the same number of protons and electron. They have no electrical charge.

Objects can become charged when electrons are transferred by:1. Conduction2. Induction3. Friction

Friction – Electrons are rubbed off one object and deposited on another object.

Conduction – transfer of electrons by direction contact

Like thermal energy, electric energy will flow from area that has more charges to an area with less charges .

Charge will move until equilibrium is reached.

Induction – movement of electrons to one part of an object because of the influence of the electric field of another object

Charges can move between two objects that are touching.

When a charge object is brought nearby, one charge is attracted to the object and the other charge is repelled by the object.

The two objects are separated while the charged rod is still nearby. Now apart, charges can no longer move from one object to the other.

Charged object is removed from the area. Two objects are now oppositely charged. What would happen if the two object were moved so they were touching again?

electrical charge at rest on an object

Static cling on clothes taken from the dryer

Rubbing your hair on a balloon

The release of electricitystored in an object

Key Idea (not in notes) When a negatively charged object comes close to a positively charged object, electrons move to “neutralize the charge”.

Key Idea (not in notes) If a neutral state (charge of zero) can not be reached, electrons will move until the number of excess electrons or protons is the same on both objects.

Spark after you run your sock feet on a carpet

Lightning – positive charges collect at the top of a cloud; Negative chares collect at the bottom of the cloud

A familiar example of static electricity discharge

You can use a device called an

electroscope to see if something is

changed.  

If the electroscope is not charge,

the metal leaves inside hand straight

down.  

When the electroscope is

charged. the two metal leaves have the same charge and they repel

each other. 

Why is it dangerous to be outside during a storm?

Thunderstorm clouds’ negative charges are usually attracted to the highest nearby positive object.

Your body carries charges too. A positive charge collects on the top of your head and a negative charge collects on your feet

If you are outside during a thunderstorm, the negative charges at the bottom of the cloud might be attract to you!

How does a lightning rod work?

Lightning strikes the lightning rod rather than the building, because the lightning rod is the tallest