How does Earth movement affect day and night?
A Judy clock, a timekeeper, four 12” x 14” display cards (one with a drawing of the Sun labeled a.m., another with a setting Sun labeled p.m.; another with a Moon labeled p.m. and another labeled a.m). The teacher will initially represent planet Earth. Selected students will serve as the Sun and timekeeper. Begin at 12 o’clock in the afternoon. Ask the timekeeper to show that time, then 1 o’clock, 2 o’clock, 3 . . . and so on. Each time the timekeeper moves an hour, the “Earth (teacher)” should rotate. At strategic points, hold up the posters to reinforce the idea of a.m and p.m. occurring as the Earth spins. This process should continue until we reach 12:00 midnight. (Although the following question may be puzzling for some, ask, “Which picture do you think represents 12 a.m?” Through this exercise, the children will eventually begin to understand why it can be dark outside during early morning hours, and why the Moon and Sun can sometimes be seen simultaneously.)
Language Arts Extra: What do you do at “? O’Clock”?
As a follow-up exercise to reinforce telling time by the hour, have the children think about things they do during certain times of a day. Provide a worksheet (see Appendix D). Based on time unit lessons covered in class, have the children write about what they do at 3:00 p.m., 12:00 p.m., a.m . . .
What is an Earth year?
It takes 365 days for our planet to revolve around the Sun. The time that it takes for the Earth to orbit our star marks one year. Let’s refer to a 12-month calendar to explore further.
Holding up calendar, ask the children to ignore the numbers seen thereon, but to instead, count by ones as you point. Begin counting and ask your students to join in. Encourage them to count to 100 and notice the pattern as you count. (Although counting to 100 is not required at this grade level, many students will catch on to the number pattern and will count further.) When you’ve reached the last number, shout, “Wow! 365!” Reinforce the opening statement by asking, “What do you think might be happening to the Earth each a day passes by?” Solicit student responses. (Someone may make the connection with planetary movement being involved.) If someone gets the answer, emphasize, “Great thinking!” Based on prior discussions, the class should begin to conceptualize a year.
Why do we have seasons?
(During the following explanation, use a globe to demonstrate where the imaginary poles would be located on our planet. Also, at strategic points throughout your discussion, use a flashlight to demonstrate how sunlight reaches certain areas of our planet based on its tilt and spin. Use the globe once more when discussing Uranus’ axis.)
The Earth’s axis is tilted in such a way that different parts of the planet receive different amounts of heat and light. When the northern portion of the Earth is tilted toward the Sun, the Sun is high in the sky. Because of this, days are longer and the weather is warmer. This type of movement and tilt causes summer. When the northern portion of the Earth is tilted away from the Sun, days are shorter and the Sun appears low in the sky. You’ve guessed it. Wintertime!
Brain Teaser:
It was shared earlier that the planet Uranus’ north and south poles at times face the Sun. If the Earth was tilted like the planet Uranus, how do you think it would affect our seasons? (Using the globe, find other countries on our planet that would have hot summers and cold winters.)
Suggested Role Play/Sing-Along Activity
: Have your students form a huge circle around the room. One quarter of the way around the circle, lay a marker designated “Spring.” Continue around and repeat this quarter-length distance, strategically placing a marker for each of the remaining seasons. Select one child to stand in the center of the circle, representing the Sun. The others will begin to sing the “Season Song,” revolving and bending slightly towards “the Sun”
only
when they land on a season. (See “Season Song” lyrics on Appendix D; music sample available on cassette at Yale-New Haven Teachers Institute.)
