Grade 3
Big 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: Moderate
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Watching the Night Sky
What do you want to know about the night sky?
What do we call scientists who study space?
Astronomers
What 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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Science
Lens Lab
Materials 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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Science
Stars
(Sung to Twinkle, Twinkle, Little Star)
Twinkle, Twinkle, Little Star
I 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 Star
Larger than the Earth by far!
Since your distance is a lot,
You look like a tiny dot.
Twinkle, Twinkle, Little Star
Very 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
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Science
Stars and the Universe
What Are Stars?
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•
•
•
•
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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.
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Science
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.
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Sizing Up Stars
Data
Star Name
C
Solar Radii
2
9
40
65
70
650
750
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Sizing Up Stars
Connected 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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