1. Unit 3: Electrical Principles
Introduction
GO D.2A DESCRIBE TECHNOLOGIES FOR TRANSFER AND CONTROL OF ELECTRICAL ENERGY

2. Unit Focus Questions: How do we obtain and use electrical energy?
What scientific principles are involved?
What approaches can we use in selecting, developing and using energy-consuming devices that are efficient and effective in their energy use?

3. Where do Charges come from?
all matter is made up of atoms
atoms are made up of electrons, protons, and neutrons
protons have a positive charge
electrons have a negative charge
neutrons have no charge
in all matter there are positive and negative charges

4. Structure of the Atom
Electron (-)
Nucleus:
protons (+) & neutrons

5. Types of Charges
when an object has a negative charge it has extra electrons
when an object has a positive charge it has a deficit of electrons
a neutral charge is the result of a balance of charge
(an equal number of positive and negative charges)
during any transfer of charge it is the electrons that move
when a charged object touches a neutral object the charged object looses its charge and becomes grounded

6. Types of Charges e- e-

7. Law of electrical Charges
Challenge
How can you use a balloon to make a pop can roll across the room without touching it?

8. Law of electrical Charges
How it Works?
You pile up electrons on one thing and use them to attract the protons in something else. When you rub a balloon on your hair, it ends up loaded with electrons. Those electrons can attract the protons in a soda can.

9. Law of electrical Charges
When you rub a balloon on your head you can then stick the balloon onto the wall, why does this happen?

10. Law of electrical Charges
Electrons go from your head to the balloon, the balloon gathers a negative charge.
The electrons in the wall move leaving a positive charge on the wall (separation of charge).
The (negative) balloon is now attracted to the (positive) wall.

11. Law of electrical Charges
Unlike charges attract.
Like charges repel.
Charged objects attract uncharged (objects).