Lesson 4 - Observing Shadow Patterns

BIG IDEA:

Shadows cast by sunlight provide evidence that the sun doesn't remain in the same place all day long.

Student's Responsibility:

• Explain that the sun appears to travel in an arc across the sky every day but it's not the sun's movement causing that apparent motion.
• Explain why the position of the sun’s arc varies throughout the day and throughout the year.
  

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Class Activity (First Visit Outside: AM) (45+ minutes):

Prepare to go outside for this activity three separate times during the day (morning, noon-ish, afternoon)...
If the weather doesn't cooperate, the videos below will easily take the place of the activity.

1. Assign Responsibility Partners.
2. Students need to bring a laptop (or handouts and a pencil).
3. Students need to sign in to Science Companion Prime and then go to this link.
4. Complete the first part of that link.

Have the following discussion outside (if the weather cooperates):

• Have the students face their shadow. Ask: Where is the sun?
• What do they observe about the sun when they face their shadow? Why does their shadow appear there?
• Where would the sun be if they faced their shadow over and over again?
• Tell them to move so their shadow is on the right side. Where is the sun? Why does their shadow appear there?
• What would they need to do to cause a shadow on their right side every time they went outside?
• Can both the sun and our shadow ever be on the same side of us? Why not?
• Can they face the sun and face their shadow at the same time? Why or why not?
  

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Classroom Discussion:

After returning to the classroom, watch the top two videos. During the second video, use a ruler on the whiteboard (with 0 cm at the base of the wooden post) to show how the length of the shadow grows and shrinks throughout the day (see photo to the right). Shout out the measurements as they change and have the students determine if it is shrinking or growing.

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Who set the first clock?

Complete this Mystery Science lesson: https://mysteryscience.com/astronomy/mystery-2/earth-s-rotation-time/74?r=6994723

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How can the sun tell you the season?

Complete this Science Mystery:
https://mysteryscience.com/astronomy/mystery-4/seasonal-changes-sun-s-path/76?r=6994723

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Second Visit Outside (around noon) (45+ minutes):

Return to the pole or improvised stick outside.

• Where is the sun?
• How did the shadow’s position, shape, or size change? What observations do they have to support their explanation? Measure lengths, widths, and apparent darkness of each shadow (umbra/penumbra).
• Did the shadow’s position, shape, or size change as they thought it would?​
• Do they think the shadow will continue to change during the day?
• What do they think caused the shadow to change? What observations do they have to support their explanation?
• Use chalk to outline the shadow cast by the pole on the ground. Have students draw the shadow using a different color on the Observing Shadows: Pole section of their online science notebooks.
• Before answering all of the questions on the link, teach the following Mini-Lesson:

Sun Trails

After looking at the images above & to the right (click on each of them), click on one of the images above and identify the summer solstice, winter solstice, fall equinox, and spring equinox at noon.

Also, what can explain why the two photos above are so different?

Hint: Latitude

ThingLink Activity:

Using the first image above, create a ThingLink that shows where the following terms are located on the image, and be sure to include a short definition of each term. Embed the image in your blog post that you will create in the next portion of the lesson:

• Summer Solstice
• Winter Solstice
• Fall Equinox
• Spring Equinox

STUDENTS: The "Answer Key" is to the right! Don't look at it until you've tried to figure it out on your own!

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Student-Driven Task (Third Visit Outside: PM) (45+ minutes):

1. Take screen shots of all of your digital drawings and questions and answers on Science Companion Prime (if the weather cooperated) and insert them into a blog post entitled, "Observing Shadow Patterns."
   
2. Put at least one photo from the Daily Photo Journal into your post at the top showing what we did today (if the weather allowed).
3. Answer the following Reflection/Synthesis Questions in your blog post.

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Reflection/Synthesis Questions:

1. How are shadows made outside in the daytime? Provide some evidence to support your answer.
2. Can shadows be made inside the classroom? If so, how?
3. Do outside shadows change during the day? If so, how? Refer to the pole or stick the class observed outside if needed.
4. Think about the time between observations of the pole’s shadow. What happened?
5. What does this (the answer to #4) tell you about the sun’s position in the sky?
6. Insert one or two photos (from mine above) into your blog post to help you explain how the sun's position appears to follow an arc throughout the day (if weather allows).
   

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