1. Honors Physics Bloom High School Mr. Barry Latham, M.A.Ed.
Static Electricity
Honors Physics
Bloom High School
Mr. Barry Latham, M.A.Ed.

2. 20.1 Electric Charge
Electrostatics- study of charges that are held in place
Positive charge of nucleus equals the negative charge of surrounding electrons (before charging)
Charged objects-
Either builds up electrons or loses electrons
NOTHING GAINS PROTONS!
Like charges- repel
Opposite charges- attract

3. Charging Net charge remains constant
Conservation of Matter & Energy & Charge
Insulator- doesn’t allow for the transfer of electrons
Conductor- allows for the transfer of electrons
Semi-conductor- BIG grey area between conductor and insulator

4. Conductors and Insulators
Electric Conductor
Metals (ie: copper, iron, silver, gold)
Electric Insulator
Glass, dry wood, plastics, rubber, cloth, and dry air

5. 20.2 Electric Force Foundational principles
Two kinds of charges: positive & negative
Charges exert forces at a distance
Forces are stronger when closer
Like charges repel; opposite charges attract

6. Ways to Charge: Conduction
Conduction- flow of charges (electrons) by touching
Rubbing a balloon on your head
Electroscope- device used to determine charge
Metal knob connected by a metal stem to two thin, lightweight pieces of metal foil
PhET “Balloons & Static Electricity”

7. Ways to Charge: Induction on Neutral Objects
Induction- separation of charges without movement from the object
Grounding- allowing charges to move relative to the charge of the Earth

8. Separating Charges on Neutral Objects
Charging an object without touching
Single object can be charged by induction through grounding

9. Coulomb’s Law Force depends on distance Force depends on charge
F proportional to 1/r2
Force depends on charge
F proportional to qAqB
F proportional to qAqB/r2
K (proportionality constant)
Magnitude on electron: 1.60x10-19 C
1 C = 6.24x1018 electrons
K= 9.0x109 Nm2/C2
Similar to BIG G for gravity

10. Coulomb’s Law Charge in Coulombs (C) of object 1
Force in Newtons (N)
Coulomb’s constant:
9.0 X 109 Nm2/C2
Distance between Charges
In Meters (m)