1. If atoms start out as neutral, how do we know which material becomes positively charged and which material becomes negatively charged?
Truemper 2016

2. An object can be…
Truemper 2016

3. Truemper 2016

4. Static Electricity

5. What Is Static Electricity?
A stationary electrical charge that is built up on the surface of a material

6. Where do charges come from?
Matter is made up of atoms. + –
atom
nucleus

7. Where do charges come from?
If electrons = protons neutral
If electrons > protons  negative charge
(gains electrons)
If electrons < protons  positive charge
(loses electrons)

8. Where do charges come from?
When a balloon rubs a piece of wool...
electrons are pulled from the wool to the balloon. + – –
The balloon has more electrons than usual.
wool
The balloon: – charged,
The wool: +charged

9. Insulators
Insulators: materials that do NOT allow electrons to flow through them easily.
Insulators can be easily charged by friction as the extra electrons gained CANNOT easily escape.

10. Conductors
Conductors: materials that allow electrons to flow through them easily.
Conductors CANNOT be easily charged by friction as the extra electrons gained can easily escape.

11. Where do charges come from?
Rubbing materials does NOT create electric charges. It just transfers electrons from one material to the other.

12. Conductors and Insulators
Copper
Rubber
Aluminum
Cloth
Humans
Hair
Water
Plastic
Most metals
Glass
Paper

13. If atoms start out as neutral, how do we know which material becomes positively charged and which material becomes negatively charged?
Truemper 2016

14. Truemper 2016

15. So which object becomes negatively charged?
Truemper 2016

16. So which object becomes negatively charged?
Truemper 2016

17. Truemper 2016

18. Aluminum becomes negatively charged
Styrofoam becomes negatively charged
Teflon becomes negatively charged
Polyethylene becomes negatively charged
Truemper 2016

19. Grounding Using a conductor to move an electric charge to the ground.
An object is grounded when it is connected to the earth.
Using a conductor to move an electric charge to the ground.

20. How does grounding occur?
When we touch a metal sphere of positive charge... + +
electrons flow from the earth to the metal to neutralize the metal. + + + –
Metal becomes neutral.

21. Grounding How does grounding occur?
Similarly, if the metal is of negative charge... – –
extra electrons flow from the metal to the earth and the metal becomes neutral. – – – –

22. Truemper SciLesson

23. Discharge
Static
Electric

24. Electric Discharge
The release of built up electrons from one charged material to a neutral or oppositely charged material.

25. What will happen as the man walks across the room?
Truemper SciLesson