1. What was the purpose of the paper clip? (It was a conducting material that completed a circuit from the battery’s positive to its negative terminal.)
2. How does the radio react to the completed circuit? (It produces static.)
3. Does a sheet of paper interfere with the radio signal? How can you tell? (No. The static is still generated when the circuit is complete.)
4. Does a sheet aluminum foil interfere with the signal? How can you tell? (Yes. The static volume decreases.)
Observing the Sun
Never look directly at the sun. The powerful energy within its electromagnetic spectrum can quickly and permanently damage your vision. You can, however, observe a projection of this nearby star. Use a thumbtack to punch a hole in the center of a sheet of heavy stock paper. Hold the paper above another sheet of paper. You’ll notice a bright spot projected onto the lower paper sheet. Move the upper sheet up and down until the image becomes a crisp circle. Although it looks like a plain spot of light, the bright dot is actually an image of the sun. During times of high sunspot activity, you can use this technique to observe sunspots.
The sun is about 93 million away. If the X-rays created by solar activity travel at the velocity of light (186,000/second), how long will it take these emissions to reach our planet? (93,000,000/186 = 500 seconds = 8.3 minutes)
Cut out or copy the sequence of sunspot images illustrated on pages 64-64. Insert these images page-by-page into a book with crisp page edges. Make sure that your frames align at the corner edge of the book. Rapidly flip through the book pages. The stack of rapidly changing frames will appear as a fluid movement.