Did You Know? People in ancient times imagined that lightening was created by an angry god.

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1 1) Check HW On the computer, check your Electrostatic Series Homework sheet by looking at the answers on the class web site. 2) Exit Card Electrostatic Series Leprechaun Question 3) Finish Yesterday's Note Find "Lesson 03 Contact and Induced Charge Separation" on the class webpage and finish copying the rest of the note. 4) John Travoltage PhET Download the "John Travoltage PhET Worksheet" from the class website and save it to your Science Folder. Follow the instructions and type out your answers on the worksheet while doing the activity. Save your answers in your Science folder then login to D2L elearning and upload your answers the 'John Travoltage PhET' dropbox. 5) Note on Electric Discharge We will fill this in together. 1

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4 Did You Know? People in ancient times imagined that lightening was created by an angry god. Thor was the mythological god of thunder and was thought of as the strongest of all the Norse gods. One of the days of the week is named after him Thursday (Thor's Day). Today we know lightening is a giant example of an electric discharge. 4

5 Conditions for Electric Discharge Review of Charging by Friction When two neutral objects rub against each other and have a different levels of attraction for their electrons, electrons will move from one object to another. Each object must be an. insulator The electrostatic series helps predict which object will gain electrons and become negative and which object lose and become. positive protons Static discharge is when electrons travel through the air from one object to another. When the electrons travel rapidly through the air, the air is heated and light is generated. This is seen as a small arc. What conditions caused the static discharge to occur? There are 3 Keys factors that influence static discharge: 1) The medium 2) The size of the charge difference 3) The distance between charged objects John Tavoltage Phet 1) Medium Definition the substance the electrons are travelling through. Examples Conductors vs. Insulators The structure of a material affects its ability to transfer electrons. A conductor allows electrons to move within the material rather easily whereas an insulator resists internal movement of electrons. Water is a better conductor than air! Humidity is a measure of the amount of water in the air. Water is a better conductor than dry air. Static buildup happens less in humid weather as the electrons that build up can dissipate to the air. 5

6 2) Size of the Charge Difference charge difference The greater the, the greater the potential for discharge. The more John rubbed his foot on the carpet, the more the chance that he was _shocked_. Damage, however, will only happen when the discharge occurs. Circle which scenario has a greater charge difference. Scenario 1 20 protons, 15 electrons Scenario protons, 248 electrons 3) Distance Between Charged Objects The smaller the distance between the charged objects, the The the greater the chance the electrons jump to the door knob. Videos on Lightning National Geo CN Tower Birth of a Bolt Lightening Strikes (6 min) (2 min) (2 min) Lightning Lightening is the arcing of a large charge build up. Consider the conditions for static discharge when answering the following 1) Why does lightning hit tall objects? 2) Why does lightning often happen during storms? 3) Why is lightning so bright and dangerous? 6

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