Electrostatic Charge: Make a Spark with Your Finger
Grade Levels: 3 - 5
- Students will observe, infer, predict, communicate, formulate hypotheses, identify and control variables, and experiment.
- Darkened room with carpeted floor
- Turn the lights off and make the room as dark as possible.
- Have students shuffle their feet across the carpet for a few steps.
- Then ask students to touch a doorknob or some other metal object. Have them watch their fingertips carefully as they touch the doorknob.
- What did they see? If they didn't see anything, try it again.
This activity is not dangerous, but it does tend to invite horseplay, so if a group of students is involved, close supervision might be needed. The objective of the activity is to see the spark that jumps between the finger and the doorknob after an electrostatic charge is built up from shuffling the feet across the room on the carpet. Students usually discover that a spark can also jump between their finger and another person's ear or nose. The spark will sometimes be felt and heard. If the room can be darkened, the spark can also be seen. If some students are frightened by the spark, they should not be required to participate.
The spark might be thought of as a miniature lightning bolt. Lightning is a huge spark of electric current that results from a buildup of static electricity in the atmosphere. When moisture in the air and other conditions are just right, in balance with the electrostatic charge, the charge will drain off due to the natural tendency to create electrically neutral conditions.
- Ask students to answer the following question. What is the spark? Have them do some research on lightning and find out how the spark from their fingers might be related to lightning. Is lightning static electricity?
- Find out about lightning safety. What things are important to do during a lightning storm and what things should they avoid doing?
Excerpted from Hands-On Science Activities for Grades 3-4.