Electricity in Materials

When you rub two materials together, they can become ____

Charged

When materials become charged, one becomes ____ and the other becomes ____

Positive, negative

T or F: We know which materials will become positively or negatively charged

True

T or F: We know why the reason materials become positively or negatively charged

False, it remains mystery

What is static cling?

When two objects of different materials rub together and become oppositely charged, causing them to stick to each other

Why can’t objects of the same material create static cling?

They will not exchange charges

Why do electrical shocks occur?

You or your clothes gain electrons by rubbing up against other materials, and when you touch another object, the electrons leave your body

What materials will cause electric shocks?

Conductors such as metals

What type of climate will cause the most electric shocks?

A dry one

When you experience electric shock, you become a short-lived ____

Electrical circuit

What type of electricity does a Van de Graff generator use?

Static

Describe the anatomy of a Van de Graff generator

There is a vertical conveyor that rubs materials together at the bottom of the tower, and a large metal ball on the top

What is the purpose of the conveyor belt in the Van de Graff generator?

To bring electrons to the top of the tower

What happens when you touch the metal sphere of a Van de Graff generator?

You become negatively charged as electrons travel into you

How much charge do you absorb through a Van de Graff generator?

A tiny fraction of a coulumb (that’s really, really small)

What is stronger: Electric force of gravitational force?

Electric force

Describe the exchange of electrons that occurs when you rub a balloon on your head

Electrons leave your hair and make it negatively charged, while your hair becomes positively charged

A typical atom has both ___ and ____ charges

Postive, negative

Describe why a negatively charged object, like a balloon you rubbed on your head, might stick to an object with 0 net charge, like a wall

The protons that make up the atoms of the neutral object will become attracted to the electrons of the negatively charged objects, and the electrons of the neutral object are repulsed by the negatively charged object

What is electric polarization?

When positive and negative charges in a molecule/object are not distributed evenly, causing one side to become more positively charged and the other to become more negatively charged

What two things does electric force depend on?

Distance and charge

What does electric force depend on the MOST?

Distance

In the charged balloon/wall example, which fundamental property of electric force is shown most?

Distance

Can atoms be naturally polarized? Why or why not?

Yes, because of their chemical bonds

What is an example of a naturally polarized molecule?

Water

Wha is the overall charge of a water molecule?

Neutral

In a water molecule, what are the electrons of the hydrogen attracted to?

The strongly positively charged oxygen nucleus

A water molecule is an example of a _____

electric dipole

What type of objects are water molecules pulled to? Why?

Any objects with a net electrical charge, because they are polarized

What makes water “sticky” and useful for washing?

They are attracted to any objects with a charge, which is a lot of things

On what kind of days, weatherwise, would you not get a lot of static eloectricity buildup?

Humid days

What are ions?

Atoms with an unequal number of protons and electrons, meaning they have an electrical charge

T or F: Water molecules are not attracted to ions

False

Why is there not a lot of static buildup during humid days?

Water molecules attract the ions that cause static buildup

What is a good conductor of heat?

Something that exchanges heat easily with its surroundings

What is a good conductor of electricity?

Something that allows electrons to easily flow through it

What makes a good conducotr?

The outer electrons are loosely bound by the nucleus

What are insulators?

Something that does not allow electrons to move freely

What are examples of conducots?

Metals like aluminum and copper

What aare examples of insulators?

Rubber and plasticc

What are wires typically made of?

Copper

What is the total net charge of a charged conductor?

Zero

What is a Faraday Cage?

Something that shields whatever is inside it from electromagnetic radiation

What are some examples of Faraday cages?

Cars and microwaves

Objects with ____ have a higher density of charge than____

Corners, flat surfaces