1. Characteristics of Electricity
Unit 3
Characteristics of Electricity

2. Unit 3
Electrical energy has allowed us to develop technologies that have enhanced our way of life

3. Hybrid
Hybrid vehicles are often used today where, one part of the vehicle uses a gasoline powered motor and also energy from an electrical motor
As oil prices continue to rise and the environmental concerns are addressed, using electricity for transportation will become even more important

4. Static Electricity is produced by electron transfer
Chapter 7
Static Electricity is produced by electron transfer

5. Objectives By the end of the lesson you should be able to:
State the 3 Laws of Electrostatics
Describe a Coulomb
Describe how a static charge is created, measured and transferred
Describe insulators and conductors

6. Physics Intro Physics: the study of energy and its uses
For this unit we will be focusing on Electrical Energy

7. Electricity Electricity is the study of the electron and its uses
Where is electricity used?
Why do we get shocked?
How do light bulbs work?
How does electricity actually flow?

8. Remember An atom has 3 subatomic particles
Proton Neutron Electron
There are positive and negative charges
Electrons move fairly easily – Proton and neutrons do not!
Add electrons = negative
Remove electrons = positive

9. Electrostatics Electrostatics = the study of non-moving electrons
The Laws of Electrostatics:
Opposite charges attract
Like charges repel
Neutral objects are attracted to any charge
An induced charge results from the movement of electrons by charged objects nearby, not by direct contact!
An electroscope measures the amount of static electricity

10. Static Charge
An excess of positive or negative charges that stay in place on an object for a relatively long period of time.
Examples: Lightning, static cling in clothes, receiving a shock when touching a door handle

11. The Coulomb Charles Coulomb: lived during the 1700s
Developed a way to measure the quantity of electrons
Named the unit the Coulomb (C)
One C equals 6.25x1018 charges
Since 1 electron = 1 negative charge
1 C = 6.25 x 1018 electrons!!

12. Did you know
Lightning contacts the ground at a speed of approximately km/h

13. Positive and Negative Charges
Charles Du Fay (1698 – 1739) discovered two types of static electric charges. Benjamin Franklin (1706 – 1790) named the two charges positive (+) and negative (-) charges.

14. Chemistry Recap
Atoms are made up of protons ( +), neutrons (0), and electrons (-).
# protons = # electrons, the atom is neutral.
Electrons orbit the nucleus and move quite easily.
Movement or transfer of electrons from one atom to another changes the charge on the atom.

15. A Neutral Atom (Lithium)

16. Chemistry Recap
When an atom loses electrons, the atom becomes more positive.
When the atom gains electrons, it becomes more negative.
Neutral objects do not have a charge.

17. Conductors Allow electrons to transfer freely
Metals are excellent conductors because they can give electrons easily eg. Copper or aluminum

18. Insulators
Materials that do not allow electrons to move easily from one location on an object to another (electrons tend to stay with the atom they are attached to).
Examples: glass, plastics, ceramics, dry wood.

19. Creating Static Electricity
Friction between two objects causes one object to lose electrons and the other object to gain electrons

20. Generating Static Charge
Friction causes objects to become charged
For example, the static charge in clouds is produced due to the friction as hot air rises rapidly in the cloud banks
The Van de Graaff generator uses friction to produce a large static charge on a metal dome using a moving belt

21. Applications
Devices in chimneys use static charge to remove small particles of dust
Plastic sandwich wrap clings use static electricity
Air Ionizers clean the air by attracting charged particles in the air
Static electricity is used in painting automobiles
Refuelling

22. Dangers of Static Electricity
Before pumping fuel you need to get rid of static electricity because they can cause an explosion
Allowing charge to flow into Earth’s surface is called grounding
Lightning rods on houses and large buildings provide a ground rather than hitting the building