Celestial Mechanics: Earth, Moon and Sun
Yesterday the Glover students built on their knowledge of the phases of the Moon with a lesson that delved into the celestial geometry that produces Moon phases and eclipses. Students performed a demonstration of the complex movements of the Earth and Moon for their classes, and learned the difference between the “dark” side of the Moon and the “far” side of the Moon. Students then worked in small groups to model these movements with balls and flashlights. They worked to understand why we see Moon phases from Earth, even though from a “space traveler” perspective (that is, outside the plane of the solar system) the Moon is always light on one side and dark on the other.
Students also modeled solar and lunar eclipses, and identified the Moon phases and the times of the year when these can occur.
Although students should now be able to distinguish first and last quarter (and similarly, waxing and waning phases) from their understanding of celestial mechanics, there is a handy mnemonic available to them as French speakers: first is “premier” in French, and last is “dernier”, so looking at the shape of the lower-case “p” and “d” will remind them of whether they are seeing the Moon in “premier quartier” or “dernier quartier”.
In our next session we will take an even broader perspective, and learn about our Solar System!