Lesson 2.4 - Light Spectra of Stars

Unit objective:

Students can develop a model using academic vocabulary to illustrate the life span of the sun and other stars and the processes in stars that release energy that eventually reaches Earth.

Lesson objective

Students can:

describe what happens to light as it goes through a prism.
explain how scientists can use light to figure out what elements make up a star.

Directions: Use the diagram below to answer questions 1-8.

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1

What happens to white light when it goes through a prism?

1

Emission Spectra of Elements

Your teacher will give you a viewing tool that acts like a prism. Be very careful not to touch the clear film in the middle of the tool as you complete your work.

1

Use the viewing tool to look at the lights in the classroom. Draw a picture of what you see.

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Now your teacher will show you light that is given off by atoms of different elements. The elements are all gases at room temperature. The atoms of each element will give off light when electricity is run through them.

1

Use the viewing tool to look at the light given off by hydrogen atoms. Draw a picture of what you see.

1

Use the viewing tool to look at the light given off by helium atoms. Draw a picture of what you see.

1

Use the viewing tool to look at the light given off by neon atoms. Draw a picture of what you see.

1

The light you saw was given off or emitted by the atoms of each element. Are the emission spectra of elements identical or different? For example, does the light you see given off by hydrogen atoms look the same as the light you saw given off by neon atoms?

Star Spectra

We just looked at the emission spectrum of light for hydrogen, helium, and neon. This represented the light given off or emitted by each element.

When scientists use telescopes to look at stars, they are studying the light given off by stars. The interior of a star produces a continuous spectrum of light, like a rainbow. Cooler gases in the outer layers of the star absorb certain wavelengths of light, causing dark lines to appear in the spectrum. The resulting absorption spectrum can tell astronomers a great deal about the star.

1

Compare the two pictures below. How is an absorption spectrum different from an emission spectrum?

Star 1

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1

How many dark lines do you see in the star's spectrum?

1

Drag the Hydrogen spectrum next to the Star Spectrum so that the edges line up. Do some of the lines on the two spectra match up?

Yes

No

1

A student claims, “The absorption spectra for elements are like fingerprints for humans”. Based on what you learned in the activity today, do you agree or disagree with this statement? Justify your answer.

1

2.4 - Light Spectra of Stars

2.4 - Light Spectra of Stars

Lesson 2.4 - Light Spectra of Stars

What happens to white light when it goes through a prism?

Use the viewing tool to look at the lights in the classroom. Draw a picture of what you see.

Use the viewing tool to look at the light given off by hydrogen atoms. Draw a picture of what you see.

Use the viewing tool to look at the light given off by helium atoms. Draw a picture of what you see.

Use the viewing tool to look at the light given off by neon atoms. Draw a picture of what you see.

The light you saw was given off or emitted by the atoms of each element. Are the emission spectra of elements identical or different? For example, does the light you see given off by hydrogen atoms look the same as the light you saw given off by neon atoms?

Compare the two pictures below. How is an absorption spectrum different from an emission spectrum?

How many dark lines do you see in the star's spectrum?

Drag the Hydrogen spectrum next to the Star Spectrum so that the edges line up. Do some of the lines on the two spectra match up?

Which elements have contributed to the spectrum of Star 2? Select all that apply

What color is the star?

What color is the star?

A student claims, “The absorption spectra for elements are like fingerprints for humans”. Based on what you learned in the activity today, do you agree or disagree with this statement? Justify your answer.

How do we know what elements make up a star?

Lesson 2.4 - Light Spectra of Stars

What happens to white light when it goes through a prism?

A rainbow is an example of a spectrum, or a band of colors that forms when light is separated out into the different colors that make up the light. What is the sequence of colors in a rainbow?

Do all colors of light travel at the same speed?

Do all colors of light travel have the same energy?

Which color of light has the highest energy?

Which color of light has the lowest energy?

Which color of light has the longest wavelength?

Which color of light has the shortest wavelength?

Use the viewing tool to look at the lights in the classroom. Draw a picture of what you see.

Use the viewing tool to look at the light given off by hydrogen atoms. Draw a picture of what you see.

Use the viewing tool to look at the light given off by helium atoms. Draw a picture of what you see.

Use the viewing tool to look at the light given off by neon atoms. Draw a picture of what you see.

The light you saw was given off or emitted by the atoms of each element. Are the emission spectra of elements identical or different? For example, does the light you see given off by hydrogen atoms look the same as the light you saw given off by neon atoms?

Compare the two pictures below. How is an absorption spectrum different from an emission spectrum?

How many dark lines do you see in the star's spectrum?

Drag the Hydrogen spectrum next to the Star Spectrum so that the edges line up. Do some of the lines on the two spectra match up?

Drag the Helium spectrum next to the Star Spectrum so that the edges line up. Do some of the lines on the two spectra match up?

Try matching the spectra of the other elements to the Star Spectrum. Do any other elements have lines that match?

Which elements have contributed to the spectrum of Star 1? Select all that apply

What color is the star?

Which elements have contributed to the spectrum of Star 2? Select all that apply

What color is the star?

Which neutral atoms have contributed to the spectrum of Star 3? Select all that apply

Which ions have contributed to the spectrum of Star 3? Select all that apply

What color is the star?

Which neutral elements have contributed to the spectrum of Star 4? Select all that apply

Which ions have contributed to the spectrum of Star 4? Select all that apply

What color is the star?

A student claims, “The absorption spectra for elements are like fingerprints for humans”. Based on what you learned in the activity today, do you agree or disagree with this statement? Justify your answer.

How do we know what elements make up a star?

A rainbow is an example of a spectrum, or a band of colors that forms when light is separated out into the different colors that make up the light. What is the sequence of colors in a rainbow?

Do all colors of light travel at the same speed?

Do all colors of light travel have the same energy?

Which color of light has the highest energy?

Which color of light has the lowest energy?

Which color of light has the longest wavelength?

Which color of light has the shortest wavelength?

Drag the Helium spectrum next to the Star Spectrum so that the edges line up. Do some of the lines on the two spectra match up?

Try matching the spectra of the other elements to the Star Spectrum. Do any other elements have lines that match?

Which elements have contributed to the spectrum of Star 1? Select all that apply

What color is the star?

What color is the star?

Which neutral atoms have contributed to the spectrum of Star 3? Select all that apply

Which ions have contributed to the spectrum of Star 3? Select all that apply

Which neutral elements have contributed to the spectrum of Star 4? Select all that apply

Which ions have contributed to the spectrum of Star 4? Select all that apply