1. Static Electricity

2. The world is filled with electrical charges:+ - + + + - - + - + + + - - - + + - - -

3. What is Charge?
Atoms are composed of protons (+), electrons (-) and neutrons. The nucleus contains the protons and neutrons and the electrons surround the nucleus.

4. What is Charge?
Protons are much larger than electrons but have an equal and opposite charge.

5. What is this electrical potential called?
Static Electricity - + + + + +

6. Static electricity
Static electricity is caused when certain materials are rubbed against each other.
Electrons can be rubbed off one material and on to another.
The material that has got extra electrons is now negatively charged
The material which has lost electrons is positively charged.

7. Static Electricity
Balloons
John Travoltage

8. Experiments with Balloons
Try to explain how each occurs.
Bending water with a balloon
Hair standing up
Light a flourescent lightbulb with a balloon.

9. Common Misconceptions about “Static” Electricity
Actually, the thing we call static electricity is an imbalance in the amounts of positive and negative charges found on the surface of an object.

10. Static electricity
It is this imbalance of positive and negative charges that causes static electricity
Briefly show the pith ball electroscope.
Both balls should be attracted to the charged rod but when they touch it they will be come charged with the same charge as the rod and then repel each other.
This may not work well in humid weather which gives you a chance to explain that the weather affects what happens – one teacher was amazed when I pointed out that static sparks when you take a jumper off are much worse in dry weather,

11. Static Electricity Explain clearly:
Why you sometimes get a shock from a car on a dry day
Why when you take off a wooly hat your hair may stand up

12. Gold leaf Electroscope

15. Positive and Negative Charge
Same charges repel

16. Positive and Negative Charge Unlike charges attract

17. Ben Franklin discovered lightening was static electricity

18. “Static” Electricity When you comb your hair and…
… bring your comb over a pile of paper bits

19. What will happen? Stamp your answer
“Static” Electricity
What will happen? Stamp your answer
A B.

20. Force on an Uncharged Particle
Initially the paper is uncharged, but the comb polarizes the charges in the paper.

21. Conductors and Insulators
A conductor is a substance through which electric charge flows readily. An insulator is a substance that strongly resists the flow of electric charge.
insulator
Conductor

22. Enlargement of 5 mm square computer chip.

23. What causes lightning?
Lightning is actually just static electricity on a much larger scale.
The rubbing is caused by air moving around

24. Thunder Cloud
In thunderclouds bottom is usually negative and top is positive.

27. Lightning
Static electricity is produced by friction between ice and water in the huge cloud

28. Thunder
When the lightning flash happens it heats the air to a temperature 5 times hotter than the surface of the sun.
This causes nearby air to expand and vibrate forming the sound we hear as thunder.
They should have covered sound so they should be aware that the sounds we hear are caused by air vibrating.

30. Belt carries the charge that must sit on the outside of the sphere

32. Operation
When the motor is turned on, the lower roller begins turning the belt.
Lower roller(silicon tape) builds a negative charge while the belt(rubber) builds a positive charge.
A strong negative charge is created in the roller.

33. Operation
It repels the electrons near the tips of the lower brush assembly causing the tips of the lower brush to be positively charged.
Electrons in the air are attracted to the brush and repelled from the roller.
This creates a very strong positive charge on the belt

35. Effect of Van De Graaf
Hair is pushed apart as all the electrons on the hair repel each other.

36. Point Discharge
Charge is more concentrated near to steep curves and points

37. + + + + + + + + + + + + + + + + + + +

38. Point Discharge + - + - + + + + + + + + + - + + + + + + + + + - - + +
Such a strong charge the air is ionised and conducts charge + - + - + + + + + + + + + - + + + + + + + + + - - + + - + + + + + + + - - +

40. Charging by
Induction

41. Making a Carrier Bag Electroscope
First Step:
Cut a strip from a carrier bag
Second Step:
Lay over a pencil in a glass beaker