Earth Science · Kindergarten–Grade 8
Sun, Moon and Seasons
The sun and moon mark days, seasons, and years. Tip the Earth, walk through a year, move the Moon around, and plant a stick to watch its shadow. The pictures are a classroom model, not a sky almanac.
Day 81 is about March 22, an equinox. Day 172 is about June 21. Day 355 is about December 21. Drag across the picture to move the day. Space plays the year.
Drag around the Earth to move the Moon. This eclipse picture only shows whether the Moon is near a crossing. It does not name the next eclipse on the calendar.
The stick is 1 m tall. Drag across the picture to move the hour. Day, tilt, and latitude stay in the sliders above.
What to watch
Earth’s axis leans about 23.4° and keeps pointing the same way as Earth goes around the sun. In June the northern half leans toward the sun: days are longer and the noon sun is higher. In December it leans away. If the lean were zero, every day would be about 12 hours long.
The Moon does not make its own light. We see the half that faces the sun. New, quarter, and full are the same Moon from different seats. Its path is tipped about 5°, so it usually passes above or below the straight line from the sun to the Earth. That is why we do not have an eclipse every month.
Spring tides come at new moon and full moon, when the sun and moon pull along the same line. Neap tides come near the quarters. A shadow stick is shortest at noon, when the sun is highest.
Original School Launch model. Day length uses the ordinary sunrise formula and skips the small effects of the equation of time and the height of the land. Nothing is saved or sent.