Static ElectricityStatic Electricity

Physics

Ms. Henry

School House Rock: Title 49 (Chapter 1)

ElectronsElectrons

Thank you Ben…Thank you Ben…

Franklin came up with the convention of calling the 2 types of charges, positive & negative.

Getting Charged…Getting Charged…Group Name

Paper Pick Up Michael H.

Tyler I. Bri M.

Gelatin Stalagmites Mitchell R.

Matt S. Haydon C.

Runaway Soda Can Alex L. Bobby A.

Eric H.

Swinging “Pith” of Death Austin K.

Wade M.

Elaine S.

Dancing Bunnies Sarah C.

Becca C.

Jessica R.

Swirling Vortex of Terror Zak N. Scott M. Cameron C

The Electroscope Jake W. Tyler F. Julee L. Kaitlyn W.

Within your groups.Within your groups.Pick one person to find your bin with

your materials.Complete the instructions with your

group. Fill out the front side of the worksheet

as you work. Prepare for a very brief presentation

to the class of your activity.Present.As other groups are presenting, you

should be completing the back side of your worksheet.

From our labs…From our labs…•Two kinds of charges were not created alone, but in pairs.•Matter normally contains both charges, positive and negative.•Contact separates them.•Charge is conserved; or individual charges are never created nor destroyed. Positive and negative charges are separated through the transfer of electrons.

Coulomb’s LawCoulomb’s Law

Electric Force depends on: ◦Distance (r)◦Charge (q)

K=9.0x109 N∙m2/C2 (when charges are measured in coulombs,

distance in meters and force in Newtons.)Vector Quantity: needs a magnitude

& direction

•1 Coulomb = 6.24x1018 electrons or protons•Elementary charge: 1.60x10-19C

(aka: Charge of a proton or electron)

Electric Force ProblemsElectric Force ProblemsWhat are you given?What do you need to figure out?What are you going to use to figure it out?

p. 550: Specific Problem Solving guidelines.

ExampleExampleA negative charge of -2.0x10-4C and a positive

charge of 8.0x10-4C are separated by 0.30m. What is the force between the two charges?

When does Coulomb’s Law When does Coulomb’s Law apply?apply?

In general, where the size of the charge is small compared to the distance between them.

The object is a sphere.

When does Coulomb’s Law When does Coulomb’s Law notnot apply?apply?

When the distribution of charge is farther from the test point than the size of the distribution itself.

HomeworkHomeworkp. 558 #26, 27, 33, 34, 36p. 559 #52, 57