Grade 3Big Idea 5: Earth in Space and Time

Topic 9 Stars – Size and Observational Tools

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Big Idea 5: Earth & Space Science

• SC.3.E.5.1 Explain that stars can be different; some are smaller, some are larger, and some appear brighter than others; all except the Sun are so far away that they look like points of light. Cognitive Complexity: High

• SC.3.E.5.5 Investigate that the number of stars that can be seen through telescopes is dramatically greater than those seen by the unaided eye. Cognitive Complexity: Moderate

• SC.3.N.3.2 Recognize that scientists use models to help understand and explain how things work.

• Cognitive Complexity: Low• SC.3.N.3.3 Recognize that all models are approximations of

natural phenomena; as such, they do not perfectly account for all observations.

• Cognitive Complexity: ModerateOffice of Academics - Department of Science

Watching the Night Sky

What do you want to know about the night sky?What do we call scientists who study space?

AstronomersWhat tools do astronomers use?

Telescopes

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How Do Telescopes Help Scientists?

• Telescopes make distant objects in space look much closer.

• They use lenses and/or mirrors to magnify what is being observed.

• Are all telescopes alike? Explain.

Telescopes

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Lens LabMaterials needed: a clear plastic bottle, water, and paper with print

Step 1: Fill the bottle with water, so there are no air bubbles. Put the cap on.Step 2: Write a prediction of what will happen when you put the bottle across the paper and look at the lines of type.Step 3: Count the number of spaces between lines on the paper that fit into one of the spaces between the lines you see through the bottle. How many times did your bottle magnifier magnify?Step 4: What happened? Did it support your prediction?

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Stars(Sung to Twinkle, Twinkle, Little Star)

Twinkle, Twinkle, Little StarI know what you really are:Giant ball of glowing gas,One of millions in a mass!Twinkle, Twinkle, Little Star,Oh, how big you really are!

Twinkle, Twinkle, Little StarLarger than the Earth by far!Since your distance is a lot,You look like a tiny dot.Twinkle, Twinkle, Little StarVery bright, yet very far!

Stars are twinkling, every one,Some are bigger than the sun!Just a twinkle in the sky!Just because you’re oh, so high!Twinkle, Twinkle, Little Star,Oh, how big you really are!

A Look at Some Constellations:Objects in the Sky

Stars and the Universe

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What Are Stars?

• Every star is a huge ball of burning gas.• Stars are very bright.• Stars come in different sizes.• Our Sun is our closet star.• All the other stars we see are very far away.• Stars are made mostly of hydrogen and helium

gas.

Why Do Big Stars Look So Tiny? Investigation

Object Size (Diameter) of Object Distance when Objects Look the Same Size

Small lid ______ centimeters wide _____meters _____ cm

Sandwich Paper Plate ______ centimeters wide _____meters _____ cm

Dinner Paper Plate ______ centimeters wide _____meters _____ cm

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Are these balls the same size?

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Why do they look the same size now?

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How are Stars different?• Stars come in all different sizes.• Our Sun is the standard used for comparing all other star

sizes.• The biggest stars are called supergiants.

Some are 500 times larger than the Sun.

• Some of the smallest stars are white dwarfs. Many are 1/100 the size of the Sun - roughly the size of Earth

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Sizing Up Stars Activity

Essential Question: How big are some of the stars in the sky?

Learning Goals:• Learn how scientists called astronomers

measure star size.• Work together in groups to solve a logic puzzle

that gives the sizes of seven stars.

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Sizing Up Stars Activity Directions

1. Students in each group must work as a team.2. Group team members need to cut up their clue cards

and cut apart the star names at the bottom of page 44.3. Each team member takes one clue card and takes

his/her turn reading their card to their group. If the clue gives information that be immediately used to identify a star’s size, then the answer is recorded. If not, continue with the reading of other clues.

4. Team members can read the clues as many times as necessary until the size if each star is known.

5. Groups share out their solutions to make sure everyone reached the same conclusions.Office of Academics - Department of Science

Sizing Up Stars Data

Star NameC

Solar Radii

29

406570

650750

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Sizing Up StarsConnected Learning

1. How do scientists measure star size?2. What units is used to talk about star size? What

does it mean?3. Were any stars on our list smaller than the sun?

How do you know?4. How much bigger than the sun is the smallest star

on our list? … the largest star on our list? How do you know?

5. What did you discover as you worked to solve the logic problem?

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What Did You Learn About the Sun and Stars?

Review: A Closer Look at the Sun and Stars

TAG Reflection:• Tell a fact you learned about the stars.

• Ask a question about something you don’t understand about stars?

• Give another idea that you learned in our study of the stars.

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