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South Carolina ETV
1101 George Rogers Boulevard
Columbia, SC 29201-4761
Phone: 803-737-3545

Static Electricity: Ah, There's the Rub! (Grades 4-5)

Master Teacher

Garrison Hall

Overview

Students will be acquainted with the concept of static electricity. After a brief demonstration and a video segment, they will explore some of its properties. This can be an introduction for a unit on current electricity or a unit on weather/ thunderstorms. Students should have some background on the parts of an atom.

SC Math/Science Standards Met

Science Achievement Standards
Area III—Matter and Energy
Strand 2: A

Math Achievement Standards
Area II—Numerical Concepts and Operations
F

Learning Objectives

Students will be able to:

• explain how a static charge is formed
• demonstrate static electricity using common objects
• describe how lightning is formed

Materials

For demonstration:

• 2 large round balloons
• black permanent magic marker
• string
• 1 wool cloth

For pairs of students:

• 1 piece of thread about 10 inches
• 1 rubber or plastic comb
• 1 balloon (do not use water balloons because they are hard to blow up)

• 1 container of assorted materials: small pieces of paper (from a hole puncher), packing Styrofoam, puffed rice cereal, wool cloth

ITV Series

Physics: What Matters, What Moves, "What Is Electricity?"

Previewing Activities

1. Demonstration 1: Before class, prepare a balloon head. Blow up and tie off a large balloon. With the magic marker, draw a face and tie a string onto the end. Suspend the balloon from the ceiling or doorway so that it is about your head height. This will be your introduction to static electricity.

When the students arrive, tell them you have a visitor in the classroom. Introduce Betty Bubble Head. Betty is a unique child. She has no body, arms or legs. The principal told you that she is very motivated and wants to be the head of the class. This particular day she has a head cold. Since she has difficulty blowing and wiping her nose, you were asked to do that. As you are conducting your class, you notice Betty's nose needs some attention. With your wool cloth, you rub her nose. (You are rubbing the balloon to produce a static charge. As you move away from the bal-loon, the rubbed part seems to point toward you). Betty is so grateful you helped her, she turns her head to follow your movement around the room. (Walk around the balloon, it will seem to look at you if you move slowly enough.) Betty gestures with her eyebrows as if she were raising her hand. When you get closer to Betty, she is so thankful that she swings over to kiss you. (The balloon will swing over to touch your face because of the static charge.)

2. Demonstration 2: Blow up a second bal-loon and rub someone's hair. If the hair is long enough, it will stand up.

Then tell the students that today we are going to study static electricity. We will explore some of its properties and see how it is manifested in nature as lightning.

Remind students about the atom and its different parts: nucleus, the inside, containing positively charged protons and neutral neutrons; and on the outside, nega- tively charged electrons.

Tell students that like charges repel each other while unlike charges attract each other. A statically charged material may even attract neutral objects. The balloon head was charged and your face was neutral so the balloon was attracted to you.

Focus for Viewing

Tell students they will be watching a segment dealing with electricity. Ask them to find out another name for amber and what happens when it is rubbed with a piece of cloth.

Viewing Activities

Segment 1: Start the video at the beginning. Pause when the narrator says, "They found when they rubbed fragments of amber with a cloth it would attract small objects." Ask what is the Greek name for amber. (Electron.) Ask what happened when the amber was rubbed? (It attracted the pin.)

Segment 2: Resume video and pause when the narrator says, "It's highly visible in nature during storms, for example." Tell students that nature has its own static electricity—lightning. Use this screen as a visual reference. Air masses rise and fall during thunderstorms. They rub against rain clouds, which cause them to become electrically charged. A positive charge is usually concentrated in the upper layers of the cloud and a negative charge is found in the lower portions. As the thunderstorm passes over the earth, it induces a positive charge on the ground below. The attraction between positive and negative charges makes the positive ground current flow up buildings, trees, and other elevated objects. When this happens, a bolt of lightning occurs.

Segment 3: Ask students to raise their hands when they hear any mention of negative or positive charges and current flowing.

Resume segment and play till the narrator says, "Ever try capturing a lightning bolt?" Tell students that we will not experiment with lightning because it is shockingly dangerous. We will explore static electricity using common everyday objects.

Post-Viewing Activities

See activities on pages 22 and 23.

Action Plan

1. Benjamin Franklin did a lot of study on electrostatics. Visit the Franklin Institute Science Museum at

Discover more about Franklin and his con-tributions as a scientist. Start a PowerPoint or HyperStudio portfolio on the history of electricity.

2. Nikola Tesla was an inventor at the turn of the century. His genius helped create much of today's technology. Find out why he is considered the "Forgotten Father of Technology" at

3. It is estimated that, at any given moment, nearly 2,000 thunderstorms are in progress over the Earth's surface and lightning strikes the Earth 100 times each second.

• Research why and how NASA studies lightning from space.
• Find out six common dangerous activities associated with lightning strikes how to avoid being hit, and first aid
  treatment at A Lightening Primer

Extensions

1. When you rub two different materials to-gether, which becomes positively charged and which becomes negative? Scientists have ranked materials in order of their ability to hold or give up electrons. This ranking is called the triboelectric series. Find this site on the Web to discover which common materials gain or lose electrons: What is Static Electricity? 2. Math: You can estimate how far away lightning strikes. The speed of light is very fast: about 186,000 miles per second. Sound is comparatively slower: about 1,100 feet per second. The light will be seen al-most instantaneously as it happens. A mile is 5,280 feet. If we round that to 5,000 and the speed of sound to 1,000, we can divide to find out how far the sound of the thunder can travel in one second. In one second, sound travels about one-fifth of a mile.

• You see the flash of lightning and start counting the seconds until you hear the thunder. If it takes five seconds for the thunder to get to your ear, how far away was the lightning? (One mile.)
  
• You see the flash of lightning and start counting the seconds until you hear the thunder. If you only get past the count of two, how far away was the lightning? (About a half mile.)

 

Activity 1

Teacher's Directions

1. Tie about 10 inches of thread around a piece of cereal. Suspend the cereal so that it does not hang close to anything else. (Your partner can hold or attach to the side of the desk.)

2. Charge the comb by rubbing it vigorously with the wool.

3. Slowly bring the comb near the cereal. It will swing to touch the comb. Hold it still until the cereal jumps away by itself.

4. Now try to touch the comb to the cereal again. It will move away as the comb approaches.

Rubbing the comb with the wool moved the electrons from the wool to the comb. The comb had a negative charge. The neutral cereal was attracted to it. When they touched, electrons slowly moved from the comb to the cereal. Now both objects have the same negative charge, and the cereal is repelled.

Activity 2

Teacher's Directions

1. Blow up a balloon and rub it vigorously with the wool.

2. Hold it over the pieces of paper or Styrofoam.

The paper and Styrofoam pieces jump onto the surface of the balloon as if by magic. The neutral paper is attracted to the charged balloon, and moves towards it.

Activity 3

Teacher's Directions

1. Rub a balloon with the wool.

2. Stick it to a clean blackboard or wall.

The balloon gains some electrons, which makes it negatively charged. When the balloon approaches the board, the negative charges are repelled and a positive charge is induced at the spot where the balloon touches the board. Because of this, the balloon sticks to the surface of the board. After a period of time, electrons will transfer from the balloon to the board and the balloon gets neutralized and falls.

Activity 4 (Optional)

Teacher's Directions

1. Turn on the faucet so that the water runs out in a small, steady stream, about one-eighth of an inch thick.

2. Charge the balloon or comb by rubbing it with the wool cloth.

3. Slowly bring the comb or balloon near the water and watch the water "bend."

The neutral water is attracted to the charged comb or balloon, and moves towards it.