Make a Star Count
This activity encourages students to observe the quality of the night sky and to
determine the number of stars that can be seen from their local area.
Only stars twinkle, the moon and planets do not. Pick a time for students to make
night-time observations of stars.
empty paper towel or toilet paper tube ( must be 3 times longer than the distance
across the opening)
scissors and ruler
Have the students measure the width of their "Observing Device" and then cut
the tube so that its length is three times its width. The tube will show just a small
section of the entire sky. Explain to students that it would take 144 such tubes to cover
the whole sky.
- 1. Make the observing device.
- 2. One by one, face in each of the 4 compass directions (North, South, West, and East).
- 3. Hold the tube 3/4 of the way up from the horizon in each direction and count the
number of stars seen through the tube. Hold the tube half-way up from the horizon and
repeat the count. Repeat the procedure again with the tube pointed a third of the way up.
Record your data.
- 4. Add up the numbers of stars for all sightings. If it takes 144 tubes to cover the
sky, then you have observed 1/12th of the sky. Multiply your sub-total by 12 to estimate
the total number of stars in the sky.
- 5. Add up and compare the three measurements in each direction. Why do you see more
stars in certain directions?
This activity is taken from the teacher's guide Live From the Stratosphere. For
more great activities contact NASA about their Passport to Knowledge projects.
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