Day and night are patterns we see every day. Day happens when the place where we live is facing the Sun, so sunlight reaches the ground and sky. Night happens when our place has turned away from the Sun, so the sky looks dark.
Learning about day and night helps young scientists understand time, shadows, sleep, and daily routines.
Earth is shaped like a ball and it spins like a top. As Earth spins, different places move into sunlight and then into darkness. The Sun does not go around Earth each day, even though it may look that way from the ground.
One full spin of Earth makes one day and night cycle, which takes about 24 hours.
Understanding Early Learners: Day and Night
The blue sky is not a blue roof around Earth. Sunlight looks white, but it contains many colours. Air spreads the blue part of sunlight around in many directions.
That scattered blue light reaches our eyes from all across the sky. Near sunrise or sunset, sunlight travels through more air before it reaches us. Much of the blue light gets scattered away, leaving reds, oranges, and pinks.
Clouds can change the view too. Thick clouds block much of the light, so daytime can look grey and dim.
Morning and evening do not become fully bright or fully dark in one instant. There is a short time of changing light called twilight. At dawn, sunlight begins to brighten the sky before the Sun appears above the horizon.
At dusk, some sunlight still reaches the sky after the Sun has gone below the horizon. This is why a room near a window may slowly brighten in the morning. Streetlights often turn on at dusk because people need extra light before night is completely dark.
Shadows give useful clues about sunlight. A shadow forms when an object blocks light. On a sunny morning, a person's shadow can look long.
As the Sun appears higher in the sky, the shadow usually becomes shorter. Later, it grows longer again in the other direction. Children can trace a playground shadow with chalk at different times.
They will see that the shadow moves and changes length. A flashlight and a small toy can model this indoors. Moving the flashlight changes the toy's shadow, much like changing the direction of sunlight changes outdoor shadows.
Day and night are different from the seasons. Summer does not happen because Earth is closer to the Sun, and winter does not happen because it is farther away. Earth is tilted slightly as it travels around the Sun.
This tilt changes how high the Sun appears and how long daylight lasts during different parts of the year. Some places have very long summer days or very long winter nights. When learning this topic, notice repeated patterns.
Watch where the Sun seems to rise and set, check the changing shape of shadows, and compare bedtime darkness in different seasons. The Moon may appear in daytime too. It shines because it reflects sunlight, and its changing shape comes from our changing view of its sunlit half.
Key Facts
- Day happens when our side of Earth faces the Sun.
- Night happens when our side of Earth faces away from the Sun.
- Earth spins, and this spinning causes day and night.
- 1 full spin of Earth = 1 day and night cycle = about 24 hours.
- The Sun is a star that gives Earth light and warmth.
- The Moon can be seen at night, but it does not make its own light.
Vocabulary
- Day
- Day is the time when sunlight reaches the part of Earth where you are.
- Night
- Night is the time when the part of Earth where you are is turned away from the Sun.
- Sun
- The Sun is the star that gives Earth light and heat.
- Earth
- Earth is the planet we live on, and it spins in space.
- Spin
- A spin is a turning motion, like a top turning around.
Common Mistakes to Avoid
- Thinking the Sun goes around Earth every day. This is wrong because Earth spins, making the Sun appear to move across the sky.
- Thinking night happens because the Sun turns off. This is wrong because the Sun keeps shining, but our side of Earth is facing away from it.
- Thinking the Moon makes night. This is wrong because night happens from Earth's spin, and the Moon is only an object we may see in the sky.
- Thinking everyone on Earth has day at the same time. This is wrong because one side of Earth can face the Sun while the other side is in darkness.
Practice Questions
- 1 Earth takes about 24 hours to make one full spin. How many hours are in 2 full spins?
- 2 If sunrise is at 6 o'clock in the morning and sunset is at 6 o'clock in the evening, how many hours of daylight are there?
- 3 A child in one country is eating breakfast in daylight while a child on the opposite side of Earth is getting ready for bed in darkness. Explain how Earth can have day in one place and night in another at the same time.