Earth's Motion – Day, Night, Time Zones and Seasons
GeographyEarth in SpaceAges 11–12
Use it with your class: students open it from a link or a QR code, with no account needed.
Next in Earth in Space
On the left, Earth orbits the Sun with its axis tilted 23.5° and always pointing the same direction; drag Earth along its orbit to pick a date (spring equinox, summer solstice, autumn equinox, winter solstice). On the right, Earth spins on its axis; the lit half is daytime. Drag the observer up or down to change latitude and see day length, night length, and season change in each hemisphere, along with the latitude where the Sun is directly overhead. Local time, time zone (15° per zone), and GMT are shown live.
Lesson: Earth's rotation and its effects; Earth's revolution around the Sun and its effects
What it shows
Earth makes two motions at once. Rotation on its axis, once every 24 hours from west to east, produces day and night and differences in local time: 15° of longitude equals one hour, the basis of time zones. Revolution around the Sun takes 365 days 6 hours, with the axis tilted 23.5° and always pointing the same way. That fixed tilt, not a changing distance from the Sun, causes the seasons, moves the overhead noon Sun between the tropics and makes day length vary with latitude, up to polar day and polar night.
How to use
Drag Earth along its orbit, or set the Day of the year, to the solstices and equinoxes and read the season in each hemisphere. Drag the observer up or down to change latitude and compare day and night length at each date. Change the Observer's longitude to see local time, time zone and GMT update. Switch to 3D for a rotatable view of the orbit, remembering that sizes and distances are not to scale.
Parameters you can change
- Day of the year (1 = Jan 1) 1–365 day
- Observer's latitude (negative = Southern Hemisphere) -90–90 °
- Observer's longitude (negative = West) -180–180 °
- Simulation speed 0.1–30 days/s
- Show equator, tropics, polar circles
Questions to explore
- On the June solstice, which hemisphere has days longer than nights, and at which latitude is the noon Sun directly overhead?
- If two places are 30° of longitude apart, how many hours apart are their local times?
- Why do the Northern and Southern Hemispheres have opposite seasons on the same date?
