Table of Contents • A Investigating Charge • B. Investigating Charge • C. Investigating Charge • D. Building an Electroscope • E What is the sign of the charge on the tapes? • F. Electrostatic Series 1A3F p 31 • G. Charging by Contact (Conduction) • H Demo: Charging by Induction • I. Induced Charge Separation • J. Demo: Ripping off Charges • K. Demo: Burning Off Charges • L. Concept Development 32.2 • M. Electrophorus

Table of Contents • N. Demo: Electrostatic Attraction • O. Demo: Electrostatic Attraction • P. Demo: Electrostatic Attraction • Q. Demo: Petri Dishes • R. Electrical Units • S. Van de Graaff Generator • T. Demo: Graphite Sphere • U. Demo: Franklin Alert • V. Demo: Glowing Ne2 • W. Demo: Fluorescent tube • X. Demo: Charge a Person • Y. Demo: Christmas Tinsel • Z. Demo: Precipitator

Table of Contents • AA. Demo: Propane Lighter Flame • AB. Demo: Aluminum Pie Pans • AC. Kelvin Water Drop Generator • AD. Construct Lyden Jar • AE. Demo: Dissectible Lyden Jar • AF. Demo: Ice Pail • AG. Demo: Plastic Peanuts in: • AH. How safe is an automobile? airplane? • AI. Why do some homes and barns have lightning rods? • AJ. Demo: Cloud Discharge • AK. Static Electricity at Gas Pump

Static Electricity Web Site Comments

Bef Aft Ch RC Bef Aft Ch RC • 25 28 3 13 18 26 8 1 • 21 25 4 7 18 24 6 5 • 20 27 7 2 17 24 7 2 • 20 25 5 6 17 21 4 7 • 20 24 4 7 15 20 5 6 • 20 24 4 7 15 14 -1 14 • 19 23 4 7 14 21 7 2

A. Investigating Charge • Need 2 4-inch (or so) pieces of • Scotch magic tape • 1. Tear off 2 pieces of 4 to 5-inch strips of scotch tape, fold a ½ inch piece over one end of each piece and stick it to the top of a table. • Label one piece ‘A’ and the other ‘B’.

A. Investigating Charge • 3. Holding the tab, pull both off the table. • 4. Bring them near each other. • 5. What do you observe? repel • 6. Repeat a few times. • 7. What do you find when you bring one of your pieces of tape near someone else’s piece of tape? repel

A. Investigating Charge 8. How does the kind of charge on A compare to the kind of charge on B? The are like charges. 9. Why? Like charges repel 13

B. Investigating Charge • Label a third piece of tape ‘C’ and a fourth ‘D’ • Place tape C on the table. Then place tape D on top of Tape C. • Pull both pieces of tape off the table together. • 4. Separate the pieces of tape.

B. Investigating Charge • Bring them near each other. • What do you observe? attracted • Record how the kind of charge on C compares to the kind of charge on D? • They are unlike charges • Unlike charges attract each other

B. Investigating Charge 8. Compare and record how tape ‘C’ and ‘D’ reacts to tape ‘A’ and ‘B’. Record how do the charges on each tape compare to the charge on the others. charge onC is like chargeonA, B charge on D is unlike charge on A, B, & C 17

C. Investigating Charge • We did: review • Attracted paper with different charged tape • We observed: • Both charged tapes attracted the tape • Conclusion:

C. Investigating Charge • Place pieces of paper on the table. • Bring tape ‘C’ and tape ‘D’ near the pieces of paper. • Record what happened • Both tapes attract the pieces of paper • 4. What do you think the sign of the charge on the pieces of paper?

E. Building an Electroscope 1E1 p 39 1F1 p 33 • foam cup, straw, scotch tape • 1. Construct an electroscope shown in the picture. • 2. Hang a piece of negative tape to it. • 3. Bring pieces of charged tape ‘C’ and ‘D’ near the hanging charged tape. • 4

4. Record what you observed. 5. Rub the white rod with wool and bring it near the charged tape on the electroscope. What happened to the tape? It is repelled 6. What is the charge on the white rod? negative

D. What is the Sign of the Chargeon the Tapes? review • We did: • Found Ben Franklin charge definition • Glass rub with silk is defined as positive • Observed: • Tape pulled from table is negative • Conclusion: • We have a reference known charge

D. What is the Sign of the Chargeon the Tapes? • glass tubing, pieceof silk • 1. How can we find out what the actual charge is on the pieces of tape? • Check the textbook or the internet to find out how the sign of a charge was defined by Ben Franklin. • Glass acquires a + charge • when rubbed with silk

D. What is the Sign of the Charge on the Pieces of Tape? • 3. Use the information to find and the record the charge on each of the pieces of tape. • ’A’ _____ (-) ‘B’ ____ (-) • ‘C’ _____ (-) ‘D’ ____ (+) Skip Electrostatic Series

Day 15 Feb 28

F. Electrostatic Series 1A3F p 17 clear rod glass white rod (PVC) Teflon Silk Rabbits fur cling wrap wool • 1. Set up the electroscope with a ‘-‘ piece of tape on it. • 2. Rub the clear rod, glass, silk, white rod, and Teflon with the rest of the items one at a time. Identify the sign of the charge on each using the electroscope.

F. Electrostatic Series 1A3F p 17 • Silk Wool Cling Rabbit • Wrap fur • clear rod ___ ___ ___ ___ • glass rod ___ ___ ___ ___ • white rod ___ ___ ___ ___ • Teflon ___ ___ ___ ___

F. Electrostatic Series 1A3F p 17 • Rank order the items from: • Materials tend to receive electrons and become NEGATIVELY CHARGED • Materials tend to lose electrons and become POSITIVELY CHARGED

F. Electrostatic Series Teflon Vinyl (PVC) Saran wrap Polyester hard rubber rubber balloon sealing wax Lucite wood paper silk cat’s fur wool nylon glass rabbit’s fur Teflon Vinyl (PVC) Cling wrap rubber balloon silk wool Clear rod Rabbits fur glass • Materials tend to • receive electrons • and become • NEGATIVELY • CHARGED • Materials tend to • lose electrons • and become • POSITIVELY • CHARGED

H. Charging by Contact 1. Rub the white rod with wool. 2. Touch sphere to white rod

H. Charging by Contact • What happened to the sphere? • If the little sphere does not continue to be repelled by the rod, continue moving the sphere along the rod until the sphere is constantly repelled by the white rod. • Why must this be done? • Rod is an insulator, charges not free to move on the rod • Charge on: Rod ___ (-) Sphere ___ (+)

H. Charging by Contact 6. Check and record the charge on white rod and sphere with your electroscope. Rod ____ Sphere ____ 7. Briefly explain what is going on. Charge on: Rod (-) Sphere _ (-) __ (+)

I. Charging by Induction • (wool, white rod, sphere on string, electroscope) • 1. Rub white rod with wool • 2. With sphere near the white rod, touch sphere with finger making sure the sphere does not touch the white rod. • 3. Check charge using the electroscope. • Rod ______ (-) Sphere _____ (+) • 4. Explain what took place.

I. Charging by Induction Remove finger. Electrons move to opposite side. Positive charges remain near rod. Electrons escape from sphere Touch with finger. Remove rod. Bring sphere near negative strip. Induction Explanation

G-1. Induced Charge Separation Inv. p 41 • 1. Rub white rod with wool 2. Place two spheres so that they are touching.

G-2. Induced Charge Separation 2. Bring rod near left sphere.

G-3. Charge Separation 3. With the charged rod still in position, separate the two spheres and place them upright on the table

G-4. Charge Separation 4. Remove the charged rod.

G-5. Charge Separation 5. With the plastic rod still charged, touch the small sphere to the charged rod until it acquires the same charge as the rod.

G-6. Charge Separation 6. Remove white rod using care not to touch the sphere.

G-7. Charge Separation 7. Bring small sphere near each large sphere. What happened?

G-8. Charge Separation What is the charge on each?

G-1. Induced Charge Separation Inv. p 41 What happened? Induced Charge movement Which charge moved? Negative only

G-9. Charge Separation Explanation Brought white charged strip near one of spheres.

G-1. Induced Charge Separation Inv. p 41

G-10. Charge Separation Spheres were separated. White rod was removed. Spheres were charged:

K. Burning Off Charges • (charged electroscope, match) • 1. Hang 2 negative charged pieces of tape on opposite sides of the electroscope horizontal arm. • 2. Bring burning match near the charged pieces of tape. • 3. Record what happens to the pieces of tape. Explain what happened.

L. Concept Development 32.2 Hand out worksheet as homework

Table of Contents