Two Rainforest Camps Under the Sky

A Rainforest Sky Study

Two research teams study the sky from clearings in tropical rainforests. Equator Camp is near the equator. North Camp is about 17 degrees north of the equator. Tall trees surround both camps, but each clearing has an open area for observing the Sun and stars. The records on this sheet are made-up examples of observations the teams could collect.

For the shadow study, each team places a straight, 100-centimeter pole upright on level ground. On one clear December day, they measure from the bottom of the pole to the tip of its shadow. They use the same pole height, measuring method, and observation times. Their clocks are adjusted so that noon is when the Sun reaches its highest position that day.

The teams also record shadow directions. At both camps, the morning shadows point northwest, the noon shadow points north, and the afternoon shadows point northeast. Nobody moves the poles during the test. Students should compare the measurements rather than assume that a shadow stays the same all day.

Earth rotates, or turns, once in about 24 hours. A place has daylight while it faces the Sun and darkness while it faces away. The teams record sunrise and sunset on two December days and one June day. These records use ordinary local clock time. Times are rounded to the nearest half hour. Treat them as exact for this worksheet.

For the star study, the Equator Camp team watches from the same spot at 8:00 p.m. on eight clear nights in each listed month. They check for two recognizable groups of stars: Orion and Scorpius. A zero means that the group was not visible on any of those observation nights, not that its stars disappeared. Keeping the viewing time and location the same helps the team compare months. A different viewing time could give different results. The graphs show only this team's observations, so predictions should describe what is likely, not what is certain.