The Sun and the Stars · Mati Learning Hub

LESSON 7.1 · SC.3.E.5.1

Stars Differ

Learning goal: Explain how stars differ in size and brightness.

What to know

Stars can be different sizes and can give different amounts of light.
Apparent brightness is affected by a star’s light and distance.
Except for the Sun, stars are so distant that they appear as points of light.

WATCH & NOTICE

What Are Stars?

From SciShow Kids

Listen for the difference between a star’s real properties and how it appears from Earth.

Open video on YouTube ↗

Think like a scientist

A star that appears faint is not necessarily small; it may be extremely far away.

STAR OBSERVATORY

Real brightness and apparent brightness are different

Choose a star model and move it farther from the observer. Its real size and light output stay the same, but how bright and large it appears can change.

Actual sizea star’s real diameterLuminositythe amount of light a star gives offApparent brightnesshow bright it looks from the observer

Model distance from observer 5 units

Star’s real propertiesMedium actual size · medium light output

light travels →

Appearance from hereModerately bright point

Distance changes appearance—not the star itself. Move the star and compare the two panels.

Concept model: sizes, brightness, and distance are simplified and are not drawn to scale.

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LESSON 7.2 · SC.3.E.5.2 · SC.3.E.5.3

The Sun Is a Star

Learning goal: Identify the Sun as our closest star and explain its appearance.

What to know

The Sun is a star that emits energy, including light.
It appears larger and brighter than other stars because it is much closer to Earth.
Apparent size is not the same as actual size.

WATCH & NOTICE

What Are Stars?

From SciShow Kids

Listen for the difference between a star’s real properties and how it appears from Earth.

Open video on YouTube ↗

Think like a scientist

A nearby lamp can look larger than a distant stadium light; distance changes appearance. The Sun is our nearby star.

OUR NEAREST STAR

Why does the Sun look larger than other stars?

Move the model star toward or away from Earth. Compare apparent size while remembering that both objects are stars.

Sunthe star closest to EarthApparent sizehow large something looksDistancespace between two objects

Observer on Earth

How the star appearsNearby: looks large and bright

Move the same model star Near Earth

The Sunnearby star · looks like a diskOther starsvery far away · look like points

The Sun appears largest because it is our closest star. Apparent size alone does not tell actual size.

Concept model: moving the star represents changing distance; real astronomical distances are enormously larger and are not to scale.

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LESSON 7.3 · SC.3.E.5.4

Gravity

Learning goal: Explore gravity as a force that can be overcome temporarily.

What to know

Gravity pulls objects toward Earth.
Other forces can lift or support an object against gravity.
When the upward force ends, gravity continues pulling.

WATCH & NOTICE

What Are Stars?

From SciShow Kids

Listen for the difference between a star’s real properties and how it appears from Earth.

Open video on YouTube ↗

Think like a scientist

Your hand lifts a ball against gravity. When released, the ball falls toward Earth.

PUSH AGAINST GRAVITY LAB

A push can overcome gravity—but only temporarily

Choose the strength of an upward push and launch the ball. The push sends it upward; gravity slows it, stops it briefly, and pulls it back toward Earth.

Forcea push or pullGravitya force pulling objects toward EarthTemporarylasting for a limited time

Upward push strength Medium

HighMiddleGround

gravity ↓

1 Push sends it up2 Gravity slows it3 Gravity pulls it down

Ready to launch. Predict how push strength will change maximum height.

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LESSON 7.4 · SC.3.E.5.5

Telescopes Reveal More

Learning goal: Explain why telescopes reveal many more stars than unaided eyes.

What to know

Telescopes collect more light than an unaided eye.
Faint objects become easier to detect.
A telescope is an observation tool; it does not create extra stars.

WATCH & NOTICE

What Are Stars?

From SciShow Kids

Listen for the difference between a star’s real properties and how it appears from Earth.

Open video on YouTube ↗

Think like a scientist

The same patch of sky contains faint stars that become visible when a telescope gathers enough of their light.

TELESCOPE LIGHT-GATHERING LAB

The stars were already there

Switch from unaided eyes to a telescope, then widen its opening. A larger opening collects more faint light, revealing stars that were present but hard to detect.

Telescopea tool that collects and focuses lightAperturethe opening that gathers lightFaintgiving too little light to see easily

Telescope opening Medium

5 stars visibleThe brightest stars are visible without a tool.

A telescope reveals faint stars by collecting more light. It does not create stars or move them closer.

Concept model: the star count demonstrates detection, not the real number of stars in the sky.

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What to know

What Are Stars?

Think like a scientist

Real brightness and apparent brightness are different

What to know

What Are Stars?

Think like a scientist

Why does the Sun look larger than other stars?

What to know

What Are Stars?

Think like a scientist

A push can overcome gravity—but only temporarily

What to know

What Are Stars?

Think like a scientist

The stars were already there

Unit 7 benchmark map