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For You To Do
1. Have you ever seen a tremendous lightning storm? Bolts of lightning ignite the sky as they streak toward the Earth. A tiny "lightning storm" also takes place when you get an electric shock. Think back to the last time you got a shock.
- a) Were you inside or outside?
- b) Was it winter or summer?
- c) What did you touch to get the shock?
- d) Include in your Active Physics log any additional details.
2. The study of lightning, shocks, and "static cling" can reveal important physics. Cut two strips of Scotch® Magic™ tape about 12 cm long. Bend one end of each strip under to form a tab. Place one strip sticky side down on a table and label the tab B, for "bottom." Place the other strip sticky side down on top of the first strip and label the tab T, for "top." With one hand, peel off the top strip using the tab. Then pick up the bottom strip with the other hand. Hold both strips apart, allowing them to hang down. Slowly bring the hanging strips toward each other, but do not let them touch.
- a) Record your observations.
- b) If the strips accelerated (moved) toward or away from each other, Newton's Second Law tells you that there must be a force. (Newton's First Law tells you that an object at rest will tend to stay at rest. Newton's Second Law says that if an object accelerates, it's being acted on by a force.) Was there a force present?
- c) If a force was present, was it attractive or repulsive? Explain.
3. Make a second set of strips as in Step 2.
- a) Predict what you think will happen if the two top strips are picked up, one from each set, and brought toward each other. Record your prediction in your Active Physics log.
Pick up the two top strips by the tabs, allowing both strips to hang down. Slowly bring them toward each other.
- b) Record your observations.
- c) Was the force attractive or repulsive? Explain.
d) Predict what you think will happen if the two bottom strips of tape are picked up and brought toward each other. Record your prediction.
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