NSDL/NSTA Web Seminar: Charging into Electrostatics LIVE INTERACTIVE LEARNING @ YOUR DESKTOP NSDL/NSTA Web Seminar: Charging into Electrostatics Tuesday, January 30, 2007 7:00 p.m. to 8:00 p.m. Eastern time

http://nsdl.org Access to multiple collections in Physics and Astronomy ComPADRE: the NSDL Physics & Astronomy Pathway PhysicsFront.org Special ComPADRE collection for secondary level teachers Still intro, mention of Pathways and NSDL http://nsdl.org

Charging into Electrostatics An NSDL/AAPT/ComPADRE Presentation by Jan Mader and Dr. Cathy Ezrailson

Test Yourself In which direction will charges move in the diagram shown: To the left To the right The electrons will not move + - Charges moved http://nsdl.org

“Static” Electricity When you comb your hair and… … bring your comb over a pile of paper bits http://nsdl.org

What will happen? Stamp your answer “Static” Electricity What will happen? Stamp your answer A. B. http://nsdl.org

“Static” Electricity The force felt by the paper bits is due to a difference in charge on the comb compared to the paper. This “force of attraction” was first observed by the Greeks who found that piece of amber (“elektron”) attracted other objects when rubbed. http://nsdl.org

Match the diagram below with its correct description. 1. 2. 3. Excess of Electrons Net Charge Negative Deficiency of Electrons Net Charge Positive Balanced atom Net Charge Zero Volunteers with separate colors: Red,Yellow, Green A. B. C. http://nsdl.org

“Static” Electricity Usually charges balance each other out, and nothing happens. But when two objects with like charges (all positive or all negative) come together, the charges repel and the objects move away from each other. Objects with opposite charges attract each other because the different charges want to balance each other.  Objects can get a negative charge by picking up electrons from other objects. http://nsdl.org

Common Misconceptions about “Static” Electricity Actually, the thing we call static electricity is an imbalance in the amounts of positive and negative charges found on the surface of an object. http://nsdl.org

Results in a transfer of charges Methods of Charging Direct contact Induction Direct contact label replaced. Picture swapped. Usually results in a temporary rearrangement of charges Results in a transfer of charges http://nsdl.org

Common Misconceptions about “Static” Electricity Lightning is like static electricity, except on a much bigger scale. Both lightning and static electricity happen because of the attraction between the opposite charges. http://nsdl.org

Self Check? Charges flow from less negative to more negative areas. True False Charges flow from less negative to more negative areas. True False Like charges repel. http://nsdl.org

Pt II: Making a Magic Tape Electroscope First Step: Bend back one end on each of two tapes to make a handle. Second Step: Lay each piece of magic tape on top of each other on a smooth surface.

Making a Magic Tape Electroscope Third Step: Pick up the tape “handles” and pull the tapes apart. http://nsdl.org

Making a Magic Tape Electroscope The tapes separate as shown. What do you think causes this to occur? 1. 2. 3.

Making a Magic Tape Electroscope Charges on the surface of the tapes shown are alike Do we know whether these charges are positive or negative? How could we tell? Write your answers on the chat http://nsdl.org

Charge Quiz What are the charges on the objects shown? Use the + or – stamp to indicate the charge on the picture Added third image, pick a volunteer from ES,MS, HS respectively How can you tell? http://nsdl.org

PT III: Charging an Electrophorus Set the pie tin down on the picnic plate. Hold it by the plastic cup. Rub the Styrofoam plate with cloth or a paper towel.

Using an Electrophorus to Store Charge Touch the foil-wrapped cardboard and the pie tin at the same time, then let go. Hold the plastic cup and lift the pie tin. Touch it to the nail on the Leyden Jar. Repeat.

The Leyden Jar The Leyden jar is a device for storing electric charge invented in 1745 by Pieter van Musschenbroek (1700–1748). Mr. Muschenbroek’s bottle is referred to as the “phial” by Benjamin Franklin. Today, we would call it a capacitor. http://nsdl.org

Charging by Induction Quiz Does the diagram below illustrate permanent or temporary charging by induction? Step I Step I I Step I I I Step IV Permanent Temporary

ThePhysicsFront Resources Let’s go to The Physics Front and look at what resources are available to you and your fellow teachers http://thephysicsfront.org http://nsdl.org

Credits Benjamin Franklin and Electrostatics by Robert Morse http://www.tufts.edu/as/wright_center/fellows/bob_morse_04/ Museum of Science, Boston, http://www.mos.org/sln/toe/staticintro.html The Weather Eye http://weathereye.kgan.com/cadet/lightning/electricity.html Practical Physics, published in 1914 by Macmillan and Company http://nsdl.org

Go to http://nsdl.org and click on the K-12 audience page Download this seminar’s companion guide with resources from the seminar and more Expert Voices blog with our presenters http://expertvoices.nsdl.org Robert concludes http://nsdl.org

THANK YOU! Robert Payo Dr. Cathy Ezrailson Jan Mader http://nsdl.org http://compadre.org ThePhysicsFront.org Dr. Cathy Ezrailson cezrailson@tamu.edu THANK YOU! Jan Mader jan_mader@gfps.k12.mt.us Robert Payo rpayo@nsdl.ucar.org

National Science Teachers Association Gerry Wheeler, Executive Director Frank Owens, Associate Executive Director Conferences and Programs Al Byers, Assistant Executive Director e-Learning NSTA Web Seminars Flavio Mendez, Program Manager Jeff Layman, Technical Coordinator Susan Hurstcalderone, Volunteer Chat Moderator LIVE INTERACTIVE LEARNING @ YOUR DESKTOP