20 Cycles in Nature: Supplemental Guide 1A | The Cycle of Daytime and Nighttime
ways. Lead students in a discussion about what they remember
about the two ways that Earth moves from the Grade 1 Astronomy
domain: Earth rotates, or spins around, its axis; Earth also orbits,
or moves in a path around, the sun. Tell students that over the next
few lessons, they will learn how these two types of movement are
directly related to the cycle of daytime and nighttime as well as to
the cycle of the four seasons.What Do We Know? 5 minutes
There are several different kinds of cycles that occur in nature.
Explain to students that some of nature’s cycles repeat quickly,
whereas other cycles take longer to repeat. Some cycles take
place every day and night! Discuss with students what they
experience when it is daytime and when it is nighttime. Have them
use their fi ve senses to describe the differences between daytime
and nighttime.Vocabulary Preview 5 minutes
Axis
Show image 1A-3: Spinning- In today’s read-aloud you will hear that Earth spins around an
imaginary line called an axis. - Say axis with me three times.
- An axis is a line through the middle of an object. [Point to the
axis of the sphere to the right.] - Earth’s axis goes from the North Pole to the South Pole. Earth
spins around its axis.
Show image 1A-4: Earth rotating on its axis - Where is Earth’s axis in this image? What does Earth do
around its axis?