Why is there day and night?

Sunrise over Earth (dem10, iStockphoto)

Sunrise over Earth (dem10, iStockphoto)
How does this align with my curriculum?
Students will learn about how the earth rotates on its axis which creates the cycle of night and day.
Overview
Activities | Timing | Student Grouping | Description |
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Minds-On: What Do We Know About Night and Day? | 10 minutes | Large group | Students share their prior knowledge about day and night. |
Action: What Causes Night and Day | 30 minutes | Small group | Students learn about what causes the cycle of day and night. |
Consolidation: Show What You Know | 15-20 minutes | Independent | Students consolidate their learning by summarizing what they know about what causes day and night. |
This lesson can be done over a few days.
Materials and Preparation
Teaching and Learning Activities
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Minds-On: What Do We Know About Night and Day? (10-15 min.)
Instructions | Teaching Tips |
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As a class, activate prior knowledge by having students share what they already know about night and day. Use a projection device to share the Day and Night KWL Chart [Google doc] [Word doc] [PDF] on a screen. Ask students to share what they know and record this information in the “Know” part. Note: Use symbols as well as or instead of words. ![]() If you are unfamiliar with KWL charts, review this page that explains in detail how to use this learning strategy. Students may need further support for triggering their knowledge. You could do this by showing students a time lapse video of night and day time such as this video or this video. Alternatively, encourage students to go outside with their trusted adults in the evening and during the day to make some observations. |
DiscussionsDiscussion prompts can include:
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Action: What Causes Night and Day (30-40 min.)
Instructions | Teaching Tips |
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Show students the slideshow Why is there day and night? [Google slides] [pptx] [PDF] ![]() As a class add student questions and new knowledge and challenge existing ideas on the KWL chart. |
LanguageCreate a word wall with images of terminology students are likely to encounter during this lesson such as Sun, Moon, Earth, axis, turn, spin, etc. Incorporate vocabulary in other relevant languages as well (e.g., French). Ask students who feel comfortable sharing some of the words they know in the language they speak about night and day. |
Using a globe and a flashlight, demonstrate how the Sun shines on the Earth. You will want to do this in a somewhat darkened room. Encourage students to notice that only one side of the globe is lit by the flashlight. This is the part of the Earth that experiences day. The other side of the globe is in shadow. This is the part of the Earth that experiences night. Slowly turn to the globe to demonstrate how the Earth rotates like the animation in the slideshow. Note: To have students take notice of the rotation, put a sticker or marker on one spot on the globe. It could be where your school is located. Students should notice how different parts of the Earth pass through the light and shadow. Ask students if they think everyone around the world sees the Sun at the same time. Have them explain why or why not. Shine the light on Australia and ask if people on the opposite side can see the Sun. and ask them if it is night or day there. To see a demonstration on how to do this watch this video. |
IdeaIf you do not have access to a globe, you could use a foam ball with a wooden skewer pushed through the centre as an axis. DiscussionsDiscussion prompts can include:
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Consolidation: Show What You Know (15-20 min.)
Instructions | Teaching Tips |
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Students could consolidate their learning about night and day by participating in the Why is there day and night? Consolidation activity [Google doc] [Word doc] [PDF]. ![]() Use a projection device to share the page. You can read the sentences and students could select the correct word or image to fill in the missing word. Responses for the reproducible include:
If using the [Google jamboard] students can drag and drop the words into the correct places in the sentences. Make a copy of the jamboard before starting. ![]() Alternatively, have a discussion with the class or with individual students using questions such as these:
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LanguageIf you are using the reproducible on an interactive whiteboard, students could write or draw images to complete the sentences. |
As a class, using a projection device, reflect on the learning and contribute to the “L” section of the KWL chart. |
Background Information for Teachers
Why is there day and night?
Measuring time has been an important phenomenon for humans. Early people told time by watching shadows move across the land. Sundials were created in order to track this progression of shadows.
Sundial, 3rd century AD (Source: Zde [CC BY-SA via Wikimedia Commons).
Image - Text Version
Shown is a colour photograph of a concave piece of stone carved with radiating lines and symbols.
The stone is shaped like the peel from a slice of orange, or a shard of a broken bowl. It is thin and curved inward, facing up to the sky.
Inside the bowl are elaborate carvings. Straight lines radiate from the centre of the top edge, like bicycle spokes. Near the bottom edge, the space between each line is labelled with a symbol. These look like letters, but not from the English alphabet.
More letters are carved into the base holding the curved piece above the brick floor below. The whole structure is pale grey, shaded with black moss or grime. This is darkest in the carved lines.
The rotation of Earth on its axis is the reason why the Sun changes position in the sky over the course of the day. This rotation is measured by the 24 hour time system. People on different parts of the planet experience day and night at different times.
Animation of Earth spinning on its axis (Source: Silver Spoon [CC BY-SA 4.0] via Wikimedia Commons).
Image - Text Version
Shown is a colour animation of Earth rotating on what looks like a toothpick through its centre.
The Earth is spinning on its axis like a top. The axis is still, at the centre, while the rest of the Earth moves around it. It is represented by a long, thin stick that points up from the North Pole, and down through the South Pole.
This is tilted, so that the northern hemisphere is more visible than the southern hemisphere. In the background, space is black, dotted with white stars.