1. Aim: How can we describe elementary charges?
Electrostatics
Aim: How can we describe elementary charges?
Do Now: Define electrostatics from its name. What do you think it involves?
Tape Demo: Rip two pieces of tape off each other and compare how they behave with each other and another students pieces. Make sure to know which pieces are top and bottom. Likes repel and opposites attract. What is observed? What can we say about the charges on the two pieces? Note: One piece has tape bent over so to tell which piece is which. Comparison done with a second set in front of class.

2. How can we define Electrostatics?
Electro- Electricity/charged particles
Static-stationary/ not moving
Electrostatics- the study of stationary charges

3. Magic Tape
What occurs when two tops or two bottoms come near each other? How about a top and bottom?
Why does this happen?
Tape Demo: Rip two pieces of tape off each other and compare how they behave with each other and another students pieces. Make sure to know which pieces are top and bottom. Likes repel and opposites attract. What is observed? What can we say about the charges on the two pieces? Note: One piece has tape bent over so to tell which piece is which. Comparison done with a second set in front of class.

4. ATOM REVIEW Matter is made up of small structures called ATOMS
Within the NUCLEUS are two types of NUCLEONS
At the center of each atom is a NUCLEUS
Orbiting the NUCLEUS are ELECTRONS
ELECTRONS
NEGATIVE charge
Orbit nucleus
PROTONS
NEUTRONS
POSITIVE charge
DO NOT MOVE
under “normal conditions”
Uncharged – NEUTRAL
DO NOT MOVE
under “normal conditions”

5. What are these charged particles?
Name two charges:
Protons and electrons
Electron are ___________.
Protons are ___________.
Describe a neutral atom.
A deficiency of electrons produces a ____ charge, while excess electrons produce a ______ charge.
Student draws a neutral atom. Let students attempt on their own! ACTIVITY.

6. Charges Laws + + - - + - Like charges repel (move away) (+ +) (- -)
Opposite charges attract (+ -) - - + -

7. Demonstration  Why does a charged object attract a neutral object?
 
- +
+  + -
  
 + 
Ex. Rods and cloth

8. Pith Balls & Charges
How will the pith ball react when brought in contact with a negatively charged rod?
Place on front of desk and show what happens when a negatively charged rod is brought close. Allow students to explain why they think this is occurring. What happens when I place the ball in between my hand and rod? Pith balls acquires charge or rod and then gets repelled, which hits hand and grounds itself to have opposite charge and repels back to rod.

9. + - Charged Objects Normally, objects are electrically NEUTRAL.
They have even numbers of protons and electrons
If an object LOSES electrons, it
becomes
POSITIVELY charged
If an object GAINS electrons, it
becomes
NEGATIVELY charged + -
Demonstrate with pith balls/packing peanuts/van de graff/sketchy tool
LACK OF ELECTRONS
EXCESS ELECTRONS

10. How do we describe static charge?
Electrons build up in one object (due to friction – rubbing) and quickly jump to another object when touched causing an electric spark or shock.

11. Note: “q” is the variable letter
The Coulomb
The basic unit of charge is the Coulomb
1e=1.6x10-19C
1C=6.25x1018e (elementary charges)
Proton: Charge= +1.6x10-19C=+1e
Electron: Charge= -1.6x10-19C=+1e
Note: “q” is the variable letter
used for CHARGE
What is the charge if I give it one electron? 2? 3?
What if I take away one electron? What do you notice about the increments?
Difference between conversions, 1C is a ton of elementary charges! 1e is a small coulomb charge!

12. Charged Objects Objects can only gain or lose multiples of
ELEMENTARY CHARGE
This plate is neutral , so the # of PROTONS = # of ELECTRONS
Number of Electrons Lost
Plate’s Elementary Charge
Plate’s Coulomb Charge 1
+1e
+1.6x10-19 C 2
+2e
+3.2x10-19 C 3
+3e
+4.8x10-19 C
The plate LACKS ELECTRONS

13. Example #1 An object has a net charge of -8x10-18 C.
How many excess electrons are on the object?

14. Envelope Activity
Work with your table to make the following charge conversions.

15. Electron and Coulomb Conversions
1) Determine the net charge on Peter after he rubs his feetsie pajamas on a rug and gains an excess of 2.5x104 electrons.
2) A metal sphere has net negative charge of -4.0x10-8 Coulombs. Determine the number of excess electrons.

16. How is a lightning bolt produced?
Clouds become NEGATIVE by rubbing against each other (friction) and picking up electrons.
When this electron build up is large you see lightning

17. SUMMARY Describe the characteristics of a… Variable letter for charge?
Proton
Neutron
Electron
Variable letter for charge?
Unit(s) for charge?
1 elementary charge = ?
How do objects gain/lose charge?
Describe the Law of Conservation of Charge