What Makes Day and Night? The Earth's Rotation
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Modeling Solar System Objects
Grade Level: K-4
Our Solar System
Science Education Standards:
Understanding about Science and Technology:
- Tools help scientists make better observations, measurements, and equipment for investigations. They help scientists see, measure and do things that they could not otherwise see, measure and do.
Science as a Human Endeavor:
- Science and technology have been practiced by people for a long time.
Short Description: In this demonstration of day and night, students learn kinesthetically as they take on the role of the Earth orbiting the rotating sun.
Summary of Activity:
Students are introduced to day and night through a whole class reading of F. Branley's What Makes Day and Night. A kinesthetic modeling of day and night allows students to experience the spinning Earth and the day/night cycle.
Duration of Activity:
This is a two-day activity. The first day's introduction is 35 minutes and the modeling of day and night takes 30 minutes on the second day.
Students should have a basic vocabulary (Sun, Earth, rotation or spin, and revolution or orbit) with which to discuss the topic of day and night.
- Book: What Makes Day and Night by Franklyn Branley
- Dark paper to cover windows
- Lamp with 200 watt bulb and shade removed
- Wrap-around map (click here (PDF, 191 KB) for a world map which can be printed and wrapped around student's waist)
Teacher Background Information:
- The Earth spins counterclockwise as seen from above with North being up. The Earth completes one full rotation every 24 hours.
- The Sun spins counterclockwise as seen from space above the Sun, with the Sun's North Pole being up.
- Not all parts of the Sun rotate at the same speed. At its equator, it takes 27 days for the Sun to complete one rotation. Near its poles, the rotation period is as much as 31 days. Please note that the Sun and Earth in the work sheet are not drawn to the actual scale of the Sun-Earth system.
Allow time to gather book, lamp, globe and other materials. Cover windows with drapes or dark paper. Print out wrap-around map and student work sheets.
- To view completed student work sheets, click on the images to the right.
- Understand that the Earth rotates, or spins, on its axis in a cyclical fashion.
- Understand how day and night occur as a result of the Earth's rotation.
- Define and identify sunrise, day, noon, sunset, and night as the Earth spins.
Day One: Reading and Questioning
- Start by investigating what your students already know about day/night rotation with a KWL chart.
- You may want to model for your students how to ask questions. A list of question-words (who, what, when, where, why, how) may be a helpful language prompt in the classroom to encourage inquiry.
- Chart everything that students know about day and night in the first column, and what they want to know about day and night in the second column.
- Read Branley's "What Makes Day and Night." Write important vocabulary (sunrise, day, noon, sunset and night) on the board as students encounter them in the reading.
- After reading and discussing the book, review questions on the KWL chart and ask if anyone can answer some of the questions now.
- Tell students they will soon be playing or taking on the role of the Earth to learn more about day and night.
- Add the new vocabulary to your "Science Word Wall."
Day Two: Kinesthetic Model
- Review the vocabulary (sunrise, day, noon, sunset, night, spin and rotation).
- Darken room and turn on lamp. Explain that the lamp represents the Sun.
- Ask a student to be the Earth. Place the wrap-around map around the student so that your town is on his/her chest. Make sure he or she can be seen by all students.
- Mark your town with a sticker and ask students to focus on it as the Earth rotates.
- Have student begin with his/her back to the lamp (night). Ask students if they think it is day or night in their town.
- Have student rotate slowly in a counterclockwise fashion, until his/her left arm is pointed to the Sun. Ask students if they think it is sunrise or still night.
- Student continues the counterclockwise rotation until he/she faces the Sun directly. Ask students what time it is now in their town. Students can see that it is noon, the middle of the day, when we get the most light from the Sun. You may need to prompt with additional questions.
- Ask student to rotate a little more. Have him/her stop when his/her right arm is pointed toward the Sun. Ask students what time of day it is. They should be able to tell you that it is sunset.
- Complete the day/night cycle by having the student return to his/her original position, with his/her back to the Sun. Students should be able to tell you that is is midnight.
- Ask students to notice what time of day it is on the other side other Earth (student's back is facing the Sun and it is noon). Explain that one half of the Earth is always light while the other is dark. Emphasize that it is the Earth's own shadow that makes the night side of the Earth dark.
- Repeat this demonstration. Select other students volunteers so that students will get a chance to view the day and night cycle several times. Explain that it takes 24 hours for the Earth to rotate completely.
- Return to the KWL chart, review students' questions and place any new answers in the final column, What we Learned. If there are still unanswered questions, decide with the class how you will research them further.
- Distribute Day and Night work sheets for students to complete.
Whole Class Demonstration
- After you have completed the demonstration with a student volunteer, ask all students to stand in a circle around the "Sun" lamp. Ask students to move apart slightly to allow them to rotate easily.
- Explain that each of them will represent the rotating Earth.
- Begin the rotation with students facing away from the Sun (night). Explain that it is the Earth's own shadow that makes the night side of the Earth dark.
- Ask them to slowly rotate counterclockwise and keep looking straight ahead.
- As they turn, each student will be able to experience night, sunset, day, noon, sunset, and, completing the cycle, return to night.
- As they turn, ask students what part of the day/night cycle they are experiencing.
- Another way to illustrate and reinforce the day/night concept is with a globe. Locate your city, state or country on the globe and place a sticker with your school name on it to mark the spot. Then using the lamp as the Sun, slowly rotate the globe and show students how the Earth rotates, resulting in day and night.
- Using the globe you can identify which countries are in daylight while your city is in darkness and vise versa.
The Day and Night work sheet will provide a graphic assessment of student understanding.
related books and websites.