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

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

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 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: A)To the left B)To the right C)The electrons will not move +---- http://nsdl.org

“Static” Electricity When you comb your hair and… … bring your comb over a pile of paper bits 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. A.B. C. Deficiency of Electrons Net Charge Positive Balanced atom Net Charge Zero Excess of Electrons Net Charge Negative 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

Methods of Charging Direct contact Induction Results in a transfer of charges Usually results in a temporary rearrangement 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? TrueFalse TrueFalse Charges flow from less negative to more negative areas. 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.

Third Step: Pick up the tape “handles” and pull the tapes apart. Making a Magic Tape Electroscope 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? How can you tell? http://nsdl.org Use the + or – stamp to indicate the charge on the picture

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

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. Using an Electrophorus to Store Charge

The Leyden Jar The Leyden jar is a device for storing electric charge invented in 1745 by Pieter van Musschenbroek (1700–1748). electric charge Pieter van Musschenbroek 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? PermanentTemporary Step I Step I I Step I I IStep IV

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/fello ws/bob_morse_04/ http://www.tufts.edu/as/wright_center/fello ws/bob_morse_04/ Museum of Science, Boston, http://www.mos.org/sln/toe/staticintro.html http://www.mos.org/sln/toe/staticintro.html The Weather Eye http://weathereye.kgan.com/cadet/lightnin g/electricity.html http://weathereye.kgan.com/cadet/lightnin g/electricity.html Practical Physics, published in 1914 by Macmillan and Company Macmillan and Company http://nsdl.org

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