- Illustration board
- Styrofoam ball
- Barbecue sticks
- Plastic straw
With this hands-on activity students will build a simple model of Earth to understand that its rotation causes the occurrence of day and night and the fact that two people on opposite sides will not experience simultaneous daytime or night-time.
The aim of this exercise is to teach students how the Earth’s motion causes the occurrence of day and night.
At the end of this activity, students should be able to:
We experience day and night alternately. Early morning, we see that the Sun rises in the east and sets by twilight in the west always. During the night, we then see the stars move slowly towards east to west direction also. Actually, the Sun and the stars do not move around us! The Earth is the one moving around the Sun.
The Earth’s rotation is like your favourite spinning toy top. The pointed tip that goes through the middle of the top is the top’s axis. Similarly, the Earth has an axis but it is not straight up. This is because the Earth is not spinning upright. The Earth is slightly tilted or leaning on its side by 23.5O degrees while spinning toward the East.
Sunlight falls only on one side of the Earth. This side of the planet will be experiencing daylight. Because the Earth is rotating, the opposite side of the Earth away from the Sun will be experiencing night. After some time, the part of the Earth experiencing daylight will experience night. Rotation of the Earth causes night and day to alternate.
Since we learned that the Earth’s axis is tilted and hence the equator is not facing the Sun directly, different places on Earth would experience unequal length of days and nights—not exactly 12 hours of day and 12 hours of night all the time.
Different places in the Earth experiences different lengths of night and day. The 12 hours of day and 12 hours of night happens only in places near the equator, for example the Philippines. Arctic and Antarctic experience polar day when the Sun stays above the horizon for more than 24 hours and polar night when night lasts for more than 24 hours.
Ask students the following questions, answers given at the end. This can be created as a quiz on a free online website which will give you feedback on individual student marks.
1) The celestial objects like the Sun, other stars, and planets appear to move in the sky. We see them rise and set…
A) From North to South
B) From South to North
C) From East to West
2) What is Earth’s spinning motion called?
3) What are the similarities between the Earth and a spinning top?
A) The top is rounded
B) The top spins on its axis
C) The top spins and stops
4) How does the Earth rotate about its axis?
A) The Earth rotates upright
B) The Earth rotates while tilted on its side
C) The Earth speeds up and slows down while spinning
5) How many degrees is the equator of the Earth tilted relative to ecliptic?
6) Every place on Earth experiences 12 hours of day and 12 hours of night always.
7) What is the explanation of your answer above?
A) Each side of the Earth receives equal amount of light
B) The Sun shines on half of the globe always
C) The axis of the Earth is tilted so some places on Earth receives more than others and some less than others
8) The Philippines experiences almost exactly 12 hours of day and 12 hours of night.
9) What is the explanation of your answer above?
A) The Philippines is near the equator
B) The Philippines is near the North Pole
C) The Philippines is near the South Pole
10) Why do we see stars shine only at night?
Answers: 1C) 2B) 3C) 4B) 5A) 6B) 7C) 8A) 9)A) 10 The stars are still there in the day time but we cannot see them as the Sun is much closer so we see it as much brighter than the stars.
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