Night and Day

Guiding Question:  "Look outside.  It's daytime.  Why?"

Objective:  Students will be able to describe why we experience night and day.

Materials:  15 Earth Balls, Light Source, Science Notebooks

Vocabulary:   Day, Night, Earth, Sun, Spin

Safety:  Remind the students that the balls they are using today are not for throwing...just for holding.

Activity - Prior Knowledge: 

  1. Conduct a Turn and Talk:  "Do all people have the same daytime?"

Activity - New Knowledge:

  1. Ask the students to discuss/solve this riddle with a partner:  A third grade student just finishes eating dinner, and then gets a phone call.  The person on the phone says, “I just finished my breakfast, how was your dinner?”  How can this be?
  2. Tell the student’s that you are going to help them solve the riddle.
  3. Have students identify a partner they will work with
  4. Give each pair of students an Earth Ball
  5. Have the students discuss this question with their partner:  “Can everyone on earth be in sunlight at the same time?”
  6. Introduce the light (SUN) in the center of the room.
  7. Instruct students to hold the earth ball up so that the “sun” is shining on it
  8. Have the students discuss this question one more time with their partner:  “Can everyone on earth be in sunlight at the same time?”
  9. Ask students how much of the earth ball is lit up by the “sun.”
  10. Have the students identify China and Minnesota on the earth ball
  11. Instruct students to turn the earth so that Minnesota is in the sun
  12. Is China in the sun?
  13. Instruct students to turn the earth so that China is in the sun
  14. Is Minnesota in the sun?
  15. Have the students discuss this question with their partner one last time:  “Can everyone on earth be in sunlight at the same time?”
  16. Read the riddle to the students one more time:  "A third grade student just finishes eating dinner, and then gets a phone call.  The person on the phone says, “I just finished my breakfast, how was your dinner?”

Wrap Up:  Have students make a claim based on evidence in their science notebook:  "I claim that ____________________ because I observed that ____________________.

For example:  "I claim that people in St. Paul and China can not both have daylight at the same time because I observed that the sun shines on just half of the earth, and St. Paul and China are on opposite sides of the earth." 

Assessment:  Have each student draw an "answer" to the riddle in their science notebook