Children discover that other planets have day and night cycles and imagine how a longer or shorter cycle might impact them. What would they do with a 700-hour day?!!
Begin by finding out what the children already know — or think they know about the day/night cycle.
- What causes day and night cycles on Earth?
- Do other planets have day and night cycles?
- If they do, what causes those cycles?
Share that other planets in our solar system do have day and night cycles caused by the rotation on their axis. However, the length of a “day” varies from 10 hours to over 5000 hours.
Mercury* - 1407 hours (59 “Earth days”)
Venus - 5815 hours (243 “Earth days”)
Earth - 24 hours (1 “Earth day”)
Mars - 25 hours (~1 “Earth day”)
Jupiter - 10 hours (~0.5 “Earth days”)
Saturn - 11 hours (~0.5 “Earth days”)
Uranus - 17 hours (~0.75 “Earth days”)
Neptune - 16 hours (~0.66 “Earth days”)
Pluto - 153 hours (6 “Earth days”)
Modified from Planetary Fact Sheet - U.S. Units
* Mercury's day — from sunrise to sunset — is 176 Earth days long. Mercury's day and night cycle is more complex because it rotates one-and-a-half times during each of its orbits around the Sun.
Invite the children to write about what their lives would be like if Earth had a much longer or much shorter rotational period.
- What would their day be like if it took Earth 176 days to go through one complete day and night cycle?
- What if they only had 6 hours of daylight?
- How might it impact what they do for fun?
- The food they eat?
- Imagine living on other planets where the day and night cycle is so different; in what ways might it affect future explorers of these planets, and how could they adjust?
Ages 8 and up
• Individual images of planets (optional)
NASA Educational Products
Connections to the National Science Standard(s)
Standards A&D (grades K–4): Use data to construct a reasonable explanation about the patterns of movement of objects in the sky, as in the day/night cycles on Earth and other planets. Use data to develop a logical argument about what life would be like on another planet based on its day/night cycle.