South Carolina ETV

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

Static Electricity (Grades 7-9)

Master Teacher

Judy Wienges

Overview

This lesson is designed to introduce students to static electricity and what causes it. Through the video students will observe how static charges are produced and how objects with like and unlike charges react to each other.

SC Math/Science Standards Met

Science Academic Standards

Process Skills: A, B, E, F
Area III—Matter and Energy
Strand 1: A
Strand 2: A
Strand 3: A

Learning Objectives

Students will be able to:

describe the charges associated with pro-tons, electrons, and neutrons
identify the conditions that produce static electricity
describe the conditions present when charged objects repel or attract each other

Materials

balloon for each student
40 cm piece of string for each student
1 piece of wool for each student
small dots from a paper punch
2 15-cm pieces of scotch tape for each student

Vocabulary

static electricity
charged
stationary
friction
negative charge
positive charge
electron
proton
neutron
repel
attract
neutral
gained

ITV Series

About Science, Lesson #16, "Static Electricity"

Previewing Activities

Place of lesson in unit sequence: Students will have an understanding of the structure of an atom and the charges of the subatomic particles (electrons and protons).

The teacher will review with the class the loca-tion and charges of the electrons and protons in regard to the atom.

Focus for Viewing

The teacher will stimulate students' curiosity by telling them that the video will explain why they often get shocked when touching a door-knob or why their hair stands up when it is being combed.

To give students a specific responsibility while viewing, the teacher will request that students listen to the explanation, which explains how static electricity is formed in regard to the electron imbalance.

Inform students that the video will be stopped periodically so the information in the video can be discussed and Activity Sheet 1 can be completed.

Viewing Activities

When the teacher pauses the video, he/she will read the question pertaining to this section of the video, allowing students time to fill in the blanks on Activity Sheet 1. The answers to the questions are in italics.

Start the video from the beginning. Pause the video after "This type of electricity, which is caused by friction or rubbing, is called static electricity."

Read, "When materials are rubbed together they become electrically charged."

"The type of electricity produced by friction or rubbing is called static electricity."

Begin the video. Pause after, "Static electricity is electricity that does not move, it remains stationary."

Read, "Static electricity is stationary since it is not a type of electricity that flows."

Begin the video. Pause after, "Protons are within the nucleus and cannot be removed."

Instruct students to complete the chart below. Provide the correct answers when students have completed the chart.

Subatomic Can be removed Particles Charge Location from atom? Yes/No

Neutron Neutral Nucleus No

Proton Positive Nucleus No
Electron Negative Outside

Nucleus Yes

Read, "The only subatomic particle which can be removed from an atom by rubbing or fric-tion is the electron because it is located outside of the nucleus."
Read, "An atom with the same number of pro-tons as electrons has no electrical charge be-cause the positive charge of the protons cancels out the negative charge of the electrons." "An atom with no charge is said to be neutral."

Begin the video. Pause after, "Thus the rubber rod becomes negatively charged and the wool becomes positively charged."

Read, "The first diagram above shows the amount of negative and positive charges found on the wool and rubber rod in the neutral state. Draw the charges as they appear on the wool and rubber rod after the rod has been rubbed with the wool." Provide students with the correct charges.
Read, "The wool had no charge before it was rubbed on the rubber rod because its atoms had the same number of protons as electrons."

Read, "The rubber rod had no charge before it was rubbed with the wool because its atoms had the same number of protons as electrons."

Read, "The rubber rod became negatively charged when rubbed with the wool because some the of the electrons were rubbed off of the wool onto the rubber rod, giving the rubber rod more electrons than protons."

Read, "Since the wool lost some electrons, it becomes positively charged because it now has more protons than electrons."

Begin the video. Pause after, "When materials become charged, they will stay that way only as long as electrons have no way to enter or leave the material."

Read, "The first diagram above shows the amount of negative and positive charges found on the silk and glass rod in the neutral state. Draw the charges as they appear on the silk and glass rod after the rod has been rubbed with the silk." Provide students with the cor-rect charges.

Read, "The silk had no charge before it was rubbed on the glass rod because its atoms had the same number of protons as electrons."
Read, "The glass rod had no charge before it was rubbed with the silk because its atoms had the same number of protons as electrons."

Read, "The glass rod became positively charged when rubbed with the silk because some of the electrons were rubbed off of the glass rod onto the silk, leaving the glass rod with less electrons than protons."

Read, "Since the silk gained some electrons, it becomes negatively charged because it now has more electrons than protons."

Read, "A material will remain charged as long as no electrons enter or leave the material."

Begin the video. Pause after, "Like charges repel."

Read, "The balloon and the rubber rod were both rubbed with wool, causing electrons to leave the wool and move onto the surface of the balloon and rod.

"Due to the increase of electrons, both the bal-loon and rod have become negatively charged." When the negatively charged rod and balloon were brought close together, they moved apart or repelled each other.

Like charges repel.

Begin the video. Pause after, "Unlike charges attract."

Read, "The balloon is negatively charged and the glass rod is positively charged because the rod lost electrons to the silk cloth during the rubbing of the silk on the glass rod."

Read, "When the positively charged glass rod is brought near the balloon, the balloon moves toward or is attracted to the glass rod."

Read, "Unlike charges attract."

Begin the video. Pause after, "These attractions are called the Law of Electrostatic Attraction and Repulsion."

Read, "The Law of Electrostatic Attraction and Repulsion deals with the attraction of objects with unlike electrical charges and those with like electrical charges."

Post-Viewing Activities

1. Hand out Activity 2 and the supplies need- ed to do the balloon exercises. Do not give out the scotch tape at this time. Once the activity sheet and supplies have been handed out, allow students to begin the procedures given on the activity sheet. Then walk around the room, monitoring student activity and answering questions or providing help as needed.

Even though the paper pieces have not been "charged," they will be attracted by the negatively charged balloon. What happens in this situation is that some of the electrons in the paper are repelled by the negative charge on the balloon, therefore these electrons move to the opposite side of the paper, leaving a positive charge on the side of the paper near the balloon. Now the paper is positively charged on one side and is attracted to the negative charge on the balloon. Later the negatively charged balloon will repel the paper.

If the humidity is high on the day you plan this activity, you may not get the results you expect since the electron build-up on the objects being rubbed is decreased by the moisture in the air.

After completing the balloon exercises, give out the scotch tape and have students follow the procedure for the next exercise on the activity sheet.

Action Plan

1. Students can research how static electricity has helped to advance technology. Some of these areas include printing (Xerox machine, laser printer), pollution control (electrostatic precipitators, ionizers, static bars), television, electronics, and radio (variable capacitor).

2. Some students may be interested in investigating the role of lightning rods, rules for lightning safety, why a car is a safe place in a thunderstorm, and why clothes stick together after being dried in the dryer?

The following Internet sites may be useful to students investigating the preceding topics.

Extensions

1. Writing and/or History: Students can research those who have contributed to the discovery and uses of static electricity:

William Gilbert (1540-1603)
Sir Thomas Brown (1605-1682)
Charles Du Fay (1698-1739)
Benjamin Franklin (1706-1790)
Robert J. Van de Graaff (1901-1967)
Chester F. Carlson (1938-)

2. Art: Students can create a poster with the lightning safety rules.