1. Static Electricity

2. Static Electricity Two types of electricity: current & STATIC
Build-up of charge in one place
Non-moving

3. Electric Charge All matter is made up of atoms
The Coulomb (C) is the unit of charge
Atoms contain
Protons (+)
Neutrons (0)
Electrons (-)

4. Electric Charge

5. Law of Electric Charges
The law of electric charges states that like charges repel, and opposite charges attract.
Protons are positively charged and electrons are negatively charged, so they are attracted to each other.

6. Law of Electric Charges
Can you think of another rule?
Charged object and a neutral object will attract each other

7. Law of Electric Charges

8. Charged Objects
Atoms do not have a charge because the number of electrons and protons cancel each other out.
Ex: 3 protons (+) & 3 electrons (-) = 0

9. Where do charges come from?
If electrons = protons  neutral
If electrons > protons  gained electrons, negative charge
If electrons < protons  lost electrons, positive charge

10. How Can You Charge Objects?
There are 3 ways objects can be charged:
Friction
Conduction
Induction
**In each of these, only the electrons move.
The protons stay in the nucleus**

11. Friction
Charging by friction occurs when electrons are transferred from one object onto another.
Rubbing materials does not create electric charges. It just transfers electrons from one material to the other.

12. How Charging by Friction Works
For example: Rubber has a much greater attraction for electrons than animal fur.
As a result, the atoms of rubber pull e- from the atoms of animal fur
This leaves both objects with an imbalance of charge:
The rubber balloon has an excess of e- so it has a negative charge
The animal fur has a shortage of e- which leaves it positively charged.
The two objects have become charged with opposite types of charges as a result of the transfer of e- from the least electron-loving material to the most electron-loving material.

13. Friction & Triboelectric Series
different materials have different affinities for e-
Materials on the (+) side tend to have a greater affinity to GIVE electrons than those on the (-) side
When two materials are rubbed together, the one which is on the (-) side can be expected to pull electrons from the material on the (+) side

14. Become positive in charge
The following materials tend to give up electrons when brought in contact with other materials. That means they will have an increase of positive (+) charges.
The materials are listed with those that have the greatest tendency to give up electrons at the top to those that barely give up electrons.
Materials that gain a positive (+) electrical charges (Tend to give up electrons)
Most (+) charges
Air
Greatest tendency for giving up electrons and becoming highly positive (+) in charge
Dry human skin
Greatest tendency of a solid to give up electrons and becoming highly positive (+) in charge
Leather
Rabbit fur
Fur is often used to create static electricity
Glass
The glass on your TV screen gets charged and collects dust
Moderate (+) charges
Human hair
"Flyaway hair" is a good example of having a moderate positive (+) charge
Nylon
Wool
Lead
A surprise that lead would collect as much static electricity as cat fur
Cat fur
Silk
Aluminum
Gives up some electrons
Least (+) charges
Paper

15. Materials that are relatively neutral
There are very few materials that do not tend to readily attract or give up electrons when brought in contact or rubbed with other materials
Materials that are relatively neutral
Cotton
Best for non-static clothes
Steel
Not useful for static electricity

16. Become negative in charge
The following materials tend to attract electrons when brought in contact with other materials. They are listed from those with the least tendency to attract electrons to those that readily attract electrons.
Least (−) charges
Wood
Attracts some electrons, but is almost neutral
Amber
Hard rubber
Some combs are made of hard rubber
Nickel, Copper
Copper brushes used in electrostatic generator
Brass, Silver
Gold, Platinum
It is surprising that these metals attract electrons almost as much as polyester
Polyester
Clothes have static cling
Styrene (Styrofoam)
Packing material seems to stick to everything
Moderate (−) charges
Saran Wrap
You can see how Saran Wrap will stick to things on (+) list
Polyurethane
Polyethylene (like Scotch Tape)
Pull Scotch Tape off (+) surface and it will become charged
Polypropylene
Vinyl (PVC)
Many electrons will collect on PVC surface
Silicon
Most (−) charges
Teflon
Greatest tendency of gathering electrons on its surface and becoming highly negative (−) in charge

17. Where do charges come from?+ – –
When a balloon rubs a piece of wool...
Electrons are pulled from the wool to the balloon
The balloon now has an excess of electrons
Balloon: negative charge
Wool: positive charge
wool

18. Generating Static Charge
Van de Graaff generators (VDG) use friction to produce large amounts of static charge.
As a rapidly moving belt moves over rollers, contact between the two results in a transfer of charge.
A moving belt produces static charge on a metal dome - the charge resulting on the dome depends on the materials used in the VDG belt and rollers.

19. Induction
An electric charge develops on a neutral object because of a nearby charged object
No transfer of electrons
Example:
When a charged plastic rod is brought near a metal plate, the negative charges on the rod attract the positive charges in the plate and repel its negative charges.
This creates a redistribution of electrical charges in the plate

20. Why does a balloon stick to a wall?
Balloon Simulation
Why does a balloon stick to a wall?

21. Conduction Charging through contact Direct transfer of charge
Excess electrons will move to a location where there is less of them

23. Induction VS Conduction

24. Conservation of Charge
When you charge something by any method, no charges are created or destroyed.
The numbers of electrons and protons stay the same. Electrons simply move from one atom to another, which makes areas that have different charges.

25. Conductors
An electrical conductor is a material in which charges can move easily.
Most metals are good conductors because some of their electrons are free to move.
Conductors are used to make wires. For example, a lamp cord has metal wire and metal prongs.
Copper, aluminum, and mercury are good conductors

26. Insulators
An electrical insulator is a material in which charges cannot move easily.
Insulators do not conduct charges very well because their electrons cannot flow freely. The electrons are tightly held in the atoms of the insulator.
The insulating material in a lamp cord stops charges from leaving the wire and protects you from electric shock.
Plastic, rubber, glass, wood, and air are good insulators.

27. Applications and Dangers
Static charge can be very useful - electrostatic filters can be used to clean air, paint automobiles, and hold objects with electrostatic attraction.
Static charge can also be dangerous - when charge builds up it can discharge and cause serious shocks, explosions or fires.
Lightning is especially dangerous - buildings can be protected with lightning rods.

28. Anything else you can think of?
Thunderstorm Safety
Avoid contact with corded phones and devices including those plugged in for recharging. 
Cordless and wireless phones not connected to wall outlets are OK to use.
Avoid contact with electrical equipment or cords. Unplug appliances and other electrical items such as computers and turn off air conditioners. Why?
Power surges from lightning can cause serious damage.
Avoid contact with plumbing. Do not wash your hands, do not take a shower, do not wash dishes, and do not do laundry.
Plumbing and bathroom fixtures can conduct electricity.
Anything else you can think of?

29. Thunderstorm Safety
Stay away from windows and doors, and stay off porches.
Avoid hilltops, open fields, the beach or a boat on the water.
Take shelter in a sturdy building. Avoid isolated sheds or other small structures in open areas.
Avoid contact with anything metal—tractors, farm equipment, motorcycles, golf carts, golf clubs, and bicycles.
If you are driving, try to safely exit the road and park. Stay in the vehicle and turn on the emergency flashers until the heavy rain ends. Avoid touching metal or other surfaces that conduct electricity in and outside the vehicle.

30. How Lightning Forms

31. Lightning
Lightning usually strikes the highest point because that point provides the shortest path for the charges to reach the ground.
Anything that sticks up or out in an area can provide a path for lightning.
Objects, such as a lightning rod, that are joined to Earth by a conductor, such as a wire, are “grounded.” Any object that is grounded provides a path for electric charges to move to Earth.
Because Earth is so large, it can give up or absorb charges without being damaged.

32. QUIZ PREP
Come up with as many questions about static electricity as you can. Share with a partner; add to your list as they add to theirs Share with another group(s) until you feel you have “all” the questions. Practice answering those questions!