Suggests using part of a videotape to give clues, but can easily be done without the video. Part of the SETI Institute Life in the Universe curriculum. These not original, but they are clearly explained by Mary Urquhart, who worked with several NASA projects. A classic activity by Guy Ottewell. A classic activity by the late Gerald Mallon is redone by Elizabeth Roettger.
Students use rolls of toilet paper to measure of the scale of the solar system.