2.02 Star Basics

Last updated about 3 hours ago

18 questions

Note from the author:

Instructions

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HS-ESS1-1

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2.02 Star Basics

Last updated about 3 hours ago

18 questions

Note from the author:

If you need help, please watch the class recording (updated 10/1/25)

Instructions

If you need help, please watch the class recording (updated 10/1/25)

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What are stars?

There is no right or wrong answer, I want to know what you think.

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The temperature of a star is related to its color.

Blue light waves have a high frequency and transmit the most energy, which is why blue stars are __________.

Red light waves have a low frequency and transmit the least energy, which is why red star are __________

Question 6

02:43

Luminosity is a measurement of the total energy a star radiates, or how "bright" it is.  The luminosity of a star is dependent on its size (radius) and color (temperature).

Most stars follow this pattern:

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This image represents the brightness of the stars in the constellation Sirius as seen from Earth.

This image represents the actual brightness of each individual star in the constellation Sirius.

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Why do stars shine?

There is no right or wrong answer, I want to know what you think.

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Draggable item		Corresponding Item

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Each element is defined by the number of protons in the nucleus.  The numbers you see on the periodic table are called atomic numbers.

The atomic number of an element on the periodic table represents the number of __________ in its nucleus.

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Elements are defined by their number of protons, but can have different numbers of neutrons.  Each version of that element is called an isotope.

This is how isotopes are written:
Sometimes the atomic number is not included because it is difficult to type a superscript and a subscript.

Consider these isotopes of the element Lithium:

This is an isotope of Carbon:
What is its atomic mass? _______ 
How many protons does it have? _______ 
How many neutrons does it have? _______ 

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Watch the animation above or click here to view in a new tab.

Stars are powered by nuclear fusion, the process of joining (fusing) the nuclei of two atoms to form a single heavier atom.  

The animation above shows how tritium (hydrogen with 2 neutrons written as 3H) and deuterium (hydrogen with 1 neutron written as 2H) fuse together to produce helium (He) and a free neutron.  During the fusion process, energy is released.

Model this process with a chemical equation:

__________ + __________ --> __________ + __________ +__________

HS-ESS1-1

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The newly-made Helium will eventually collide with another Helium and fuse to produce Beryllium.

That Beryllium could collide with another Helium to produce Carbon.

That Carbon could collide with another Helium to produce Oxygen.

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Play the Fe[26] game or watch this video to observe how stars can produce heavier and heavier elements.

It doesn't look like a star, but watch how new elements are produced as deuterons and tritium (Hydrogen) boxes move next to ("collide") with other atoms.  This game simulates gravity how gravity pushes Hydrogen elements together so close and with such a force that sometimes these elements fuse into heavier elements.

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Bonus!

Another way to visualize nuclear fusion

If you need help, please watch the class recording (updated 10/1/25)

If you need help, please watch the class recording (updated 10/1/25)

Before we jump into Unit 2, please rate yourself on the Unit 2 objectives from 1 (just starting) to 5 (mastered it!)

You may need to scroll horizontally to see all options

	1 - getting started	2	3	4	5 - mastered it
Describe how stars are powered by nuclear fusion
Analyze and characterize stars by their physical and chemical properties
Compare the life cycles of low mass and high mass stars
Explain how stars produce the elements that make up everything

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What are stars?

There is no right or wrong answer, I want to know what you think.

Required

2

The temperature of a star is related to its color.

Blue light waves have a high frequency and transmit the most energy, which is why blue stars are __________.

Red light waves have a low frequency and transmit the least energy, which is why red star are __________

Question 6

02:43

Luminosity is a measurement of the total energy a star radiates, or how "bright" it is.  The luminosity of a star is dependent on its size (radius) and color (temperature).

Most stars follow this pattern:

1

Draggable item		Corresponding Item

This image represents the brightness of the stars in the constellation Sirius as seen from Earth.

This image represents the actual brightness of each individual star in the constellation Sirius.

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0

How could you explain the difference between the brightness of stars we see on Earth versus the actual brightness of stars?

A small red star appears brighter than a large blue star to an observer on Earth. Which star is closer to the Earth?

Large blue star

Small red star

They are the same distance

A large blue star and small red star are the same distance from the Earth. Which one would appear brighter in the night sky?

Small red star

Large blue star

There would be no difference

Required

0

Why do stars shine?

There is no right or wrong answer, I want to know what you think.

Chemistry Review!

Atoms are made of protons and neutrons in the nucleus surrounded by electrons.

Match the subatomic particle to its charge.

Draggable item		Corresponding Item
electron		positive
proton		no charge
neutron		negative

Which 2 subatomic particles are found in the nucleus of an atom and contain the majority of the atom's mass?

proton

electron

neutron

Each element is defined by the number of protons in the nucleus.  The numbers you see on the periodic table are called atomic numbers.

The atomic number of an element on the periodic table represents the number of __________ in its nucleus.

Elements are defined by their number of protons, but can have different numbers of neutrons.  Each version of that element is called an isotope.

This is how isotopes are written:
Sometimes the atomic number is not included because it is difficult to type a superscript and a subscript.

Consider these isotopes of the element Lithium:

This is an isotope of Carbon:
What is its atomic mass? _______ 
How many protons does it have? _______ 
How many neutrons does it have? _______ 

Watch the animation above or click here to view in a new tab.

Stars are powered by nuclear fusion, the process of joining (fusing) the nuclei of two atoms to form a single heavier atom.  

The animation above shows how tritium (hydrogen with 2 neutrons written as 3H) and deuterium (hydrogen with 1 neutron written as 2H) fuse together to produce helium (He) and a free neutron.  During the fusion process, energy is released.

Model this process with a chemical equation:

__________ + __________ --> __________ + __________ +__________

The newly-made Helium will eventually collide with another Helium and fuse to produce Beryllium.

That Beryllium could collide with another Helium to produce Carbon.

That Carbon could collide with another Helium to produce Oxygen.

Required

1

This process demonstrates how each additional helium collision leads to the creation of __________ elements.

Play the Fe[26] game or watch this video to observe how stars can produce heavier and heavier elements.

It doesn't look like a star, but watch how new elements are produced as deuterons and tritium (Hydrogen) boxes move next to ("collide") with other atoms.  This game simulates gravity how gravity pushes Hydrogen elements together so close and with such a force that sometimes these elements fuse into heavier elements.

Required

1

Bonus!

Another way to visualize nuclear fusion

Before we jump into Unit 2, please rate yourself on the Unit 2 objectives from 1 (just starting) to 5 (mastered it!) 

You may need to scroll horizontally to see all options

1 - getting started

2

3

4

5 - mastered it

Describe how stars are powered by nuclear fusion

Analyze and characterize stars by their physical and chemical properties

Compare the life cycles of low mass and high mass stars

Explain how stars produce the elements that make up everything

Stars can be different colors!

What color stars do you think are the hottest?

red

yellow

blue

Stars can be different colors!

What color stars do you think are the least hot?

red

yellow

blue

All stars are the same size.

True

False

How does a star's size and color usually relate to its luminosity?

Draggable item		Corresponding Item
Large Blue Star (10000 K)		Least luminosity (dimmest)
Medium Yellow Star (7500 K)		Most luminosity (brightest)
Small Red Star (3500 K)		Medium luminosity (the Sun)

How could you explain the difference between the brightness of stars we see on Earth versus the actual brightness of stars?

A small red star appears brighter than a large blue star to an observer on Earth.  Which star is closer to the Earth?

Large blue star

Small red star

They are the same distance

A large blue star and small red star are the same distance from the Earth.  Which one would appear brighter in the night sky?

Small red star

Large blue star

There would be no difference

Chemistry Review!

Atoms are made of protons and neutrons in the nucleus surrounded by electrons.

Match the subatomic particle to its charge.

electron

positive

proton

no charge

neutron

negative

Which 2 subatomic particles are found in the nucleus of an atom and contain the majority of the atom's mass?

proton

electron

neutron

This process demonstrates how each additional helium collision leads to the creation of __________ elements.

What happens when there is no more hydrogen or helium to collide with?

The star has run out of fuel and dies

The star merges with another star

The star can produce energy forever

Stars can be different colors!

What color stars do you think are the hottest?

red

yellow

blue

Stars can be different colors!

What color stars do you think are the least hot?

red

yellow

blue

All stars are the same size.

True

False

How does a star's size and color usually relate to its luminosity?

Large Blue Star (10000 K)

Least luminosity (dimmest)

Medium Yellow Star (7500 K)

Most luminosity (brightest)

Small Red Star (3500 K)

Medium luminosity (the Sun)

What happens when there is no more hydrogen or helium to collide with?

The star has run out of fuel and dies

The star merges with another star

The star can produce energy forever

2.02 Star Basics

2.02 Star Basics

If you need help, please watch the class recording (updated 10/1/25)

If you need help, please watch the class recording (updated 10/1/25)

What are stars?There is no right or wrong answer, I want to know what you think.

Why do stars shine?There is no right or wrong answer, I want to know what you think.

If you need help, please watch the class recording (updated 10/1/25)

If you need help, please watch the class recording (updated 10/1/25)

Before we jump into Unit 2, please rate yourself on the Unit 2 objectives from 1 (just starting) to 5 (mastered it!) You may need to scroll horizontally to see all options

What are stars?There is no right or wrong answer, I want to know what you think.

How could you explain the difference between the brightness of stars we see on Earth versus the actual brightness of stars?

A small red star appears brighter than a large blue star to an observer on Earth. Which star is closer to the Earth?

A large blue star and small red star are the same distance from the Earth. Which one would appear brighter in the night sky?

Why do stars shine?There is no right or wrong answer, I want to know what you think.

Chemistry Review!Atoms are made of protons and neutrons in the nucleus surrounded by electrons.Match the subatomic particle to its charge.

Which 2 subatomic particles are found in the nucleus of an atom and contain the majority of the atom's mass?

Stars can be different colors!What color stars do you think are the hottest?

Stars can be different colors!What color stars do you think are the least hot?

All stars are the same size.

How does a star's size and color usually relate to its luminosity?

How could you explain the difference between the brightness of stars we see on Earth versus the actual brightness of stars?

What happens when there is no more hydrogen or helium to collide with?

What are stars?

There is no right or wrong answer, I want to know what you think.

Why do stars shine?

There is no right or wrong answer, I want to know what you think.

Before we jump into Unit 2, please rate yourself on the Unit 2 objectives from 1 (just starting) to 5 (mastered it!)

You may need to scroll horizontally to see all options

What are stars?

There is no right or wrong answer, I want to know what you think.

Why do stars shine?

There is no right or wrong answer, I want to know what you think.

Chemistry Review!

Atoms are made of protons and neutrons in the nucleus surrounded by electrons.

Match the subatomic particle to its charge.

Stars can be different colors!

What color stars do you think are the hottest?

Stars can be different colors!

What color stars do you think are the least hot?