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Warm-Up Exercises. Get a copy of the test and your scantron . Complete your Energy and Machine Test Analysis. New Standard. S8P5. Students will recognize characteristics of gravity, electricity, and magnetism as major kinds of forces acting in nature.
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Warm-Up Exercises Get a copy of the test and your scantron. Complete your Energy and Machine Test Analysis.
New Standard • S8P5. Students will recognize characteristics of gravity, electricity, and magnetism as major kinds of forces acting in nature. • Demonstratethe advantages and disadvantages of series and parallel circuits and how they transfer energy. • Investigateand explainthat electric currents and magnets can exert force on each other.
Essential Question Why do some clothes stick together when they come out of the dryer?
Standard for today’s lesson S8P5 Students will recognize characteristics of gravity, electricity, and magnetism as major kinds of forces acting in nature.
Demonstratethe advantages and disadvantages of series and parallel circuits and how they transfer energy. • Investigateand 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! 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.
Law of Electric Charges 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.
Electric Force the force (a push or a pull) on a charged object due to an electric field Note: Like charges push Unlike charges pull
Electric Field the space around a charged object in which another charged object experiences an electric force
Remember (not in notes): Most objects have approximately the same number of protons and electron. They have no electrical charge.
So... how does an object become charged?
Objects can become charged when electrons are transferred by: 1. Conduction 2. Induction 3. Friction
Friction – Electrons are rubbed off one object and deposited on another object.
Like thermal energy, electric energy will flow from area that has more charges to an area with less charges .
Induction – movement of electrons to one part of an object because of the influence of the electric field of another object
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?
Static Electricity electrical charge at rest on an object
Examples of Static Electricity Static cling on clothes taken from the dryer Rubbing your hair on a balloon
Electrical Discharge The release of electricity stored 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.
Examples of Electric Discharge 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
How can you see if static electricity is present? You can use a device called an electroscope to see if something is changed.
How can you see if static electricity is present? If the electroscope is not charge, the metal leaves inside hand straight down.
How can you see if static electricity is present? When the electroscope is charged. the two metal leaves have the same charge and they repel each other.
Check Point Why is it dangerous to be outside during a storm?
Check Point answer Thunderstorm clouds’ negative charges are usually attracted to the highest nearby positive object.
Check Point answer Your body carries charges too. A positive charge collects on the top of your head and a negative charge collects on your feet
Check Point answer If you are outside during a thunderstorm, the negative charges at the bottom of the cloud might be attract to you!
Check Point How does a lightning rod work?
Lightning strikes the lightning rod rather than the building, because the lightning rod is the tallest