Static Electricity What Is Static Electricity?

Attraction of uncharged objects

• Similarly, when charged rod is close to paper scrap...

• -

• -

• -

• -

• -

• -

• -

• molecules of paper align.

•  attraction between the rod and + charge > repulsion between the rod and - charge.

• paper

• +

• –

• +

• –

• +

• –

• +

• –

• +

• –

• +

• –

• +

• –

• +

• –

• attraction

• repulsion

• Static

• Electricity

Static Discharge

• Human body can not feel less than 2,000 volts of static discharge
• Static charge built up by scuffing shoes on a carpet can exceed 20,000 volts?

Gas Station Fires

• Carol said a static gas pump fire is blamed for burning her daughter so badly she needed skin grafts on her legs.
• Carol had put the gas pump nozzle on automatic and re-entered her car to write a check. When her then-12-year-old daughter, wearing a sweater and jacket that may have created static electricity, reached for the nozzle, flames suddenly ignited her clothing.

• 1 If the balloon can attract some paper scraps, which of the following cannot be the charge of paper scraps?

• A Neutral B Positive
• C Negative

• A balloon has a negative charge when rubbed by a woollen cloth.

• 2 During rubbing, what have been transferred between the woollen cloth and the balloon?

• A Electrons B Protons
• C Neutrons

• A balloon has a negative charge when rubbed by woollen cloth.

How does a positively charged rod attract a neutral object?

• When a + charged rod is put near neutral object, ______________ is induced on the side of the object near the rod and _____________ is induced on the side away from the rod. The rod can attract the netural object because _________ between rod and – induced charge > the ________ between rod and + induced charge.

• How does a positively charged rod attract a neutral object?

• negative charge

• positive charge

• attraction

• repulsion

Grounding

• An object is grounded when it is connected to the earth through a connecting wire.

• What is grounding?

• If a charged conductor is grounded, it will become neutral.

Grounding

• b How does grounding occur?

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• +

• +

• +

• +

• When we touch a metal ball of positive charge...

• electrons flow from the earth to the metal ball to neutralize the metal ball.

• –

• Metal ball becomes neutral.

Grounding

• Similarly, if the metal ball is of negative charge...

• How does grounding occur?

• –

• –

• –

• –

• –

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• extra electrons flow from the metal ball to the earth and the ball becomes neutral.

Why do gasoline tankers usually have metal chains at the back?

• Why do gasoline tankers usually have metal chains at the back?

• When cars run, their tires and bodies are usually charged by _______. For gasoline tankers, if the accumulated charge is large enough, _______can be produced and _________ will occur if gasoline vapor is ignited. Those metal chains conduct the charge on the bodies of tankers to the _______ and avoid the danger.

• friction

• sparks

• explosion

• ground

Lightning

• kills more than 60 people and
• injures more than 400 people a year in the US

• one mile every five seconds
• about 20,000 C
• Voltage of up to 1.2x108 volts

Limit Exposure

Do Now

• Write a paragraph about the cartoon. Tell what he is trying to do. Will it work and why? What do you think will happen? Use the following words, static electricity, lightning, electrons, positive and negative charges.

The End

Directory: jsat -> powerpoint
powerpoint -> Nonrenewable and renewable resources
powerpoint -> Nature of Energy
powerpoint -> Making a Difference One Watt at a Time Introduction
powerpoint -> Static Electricity What Is Static Electricity?
powerpoint -> A matter of Fact Mixtures, Elements and Compounds Mixtures, elements, compounds
powerpoint -> Investigating Atoms and Atomic Theory
powerpoint -> Understanding Heat Transfer, Conduction, Convection and Radiation Heat Transfer

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