Download Spectroscope Lab

How do we know that the sun is a star? Simple! The spectroscope
patterns of the sun and the stars are very similar.
What is a Spectroscope?
Our sun is a star. Everyone knows this now. But the early scientists
did not believe this. There was no proof! The key to the proof came in 1850
with the invention of the spectroscope (SPECK-truh-scope).
A spectroscope identifies elements by the colors they give off.
Understanding the Spectroscope
The most important part of a spectroscope is a prism. A prism is
glass shaped like a wedge or a triangle.
Every substance gives off light when it becomes hot enough. Every
element gives off its own special color. A spectroscope separates the light
into colored lines. We call these lines a spectrum. A spectrum is like a
fingerprint. No two people have the same finger prints. And, no two
elements have the same spectrum. But the spectrum is always the same for a
particular element.
For example:
1.
This is what a sodium spectrum looks like.
Yellow bands
Only sodium looks like this. No other element looks exactly
like this.
2.
This is what a potassium spectrum looks like.
Purple band
Red bands
Only potassium looks like this. No other element looks exactly
like this.
There are 92 naturally occurring elements. We know the spectrum
for each one. About 67 of them have been found in sunlight. This means
that the sun contains at least 6 elements that are found on earth.
FIGURE A
A prism can break up white light into a rainbow of colors. This is
the spectrum of white light. In a spectroscope, a prism forms spectrums of
individual elements.
Identifying Spectrums
Spectrum 1
Figure B shows the spectrums of 9 elements. The numbers
represent wavelengths of color.
Spectrum 2
Figure C
Spectrum 3
Spectrum
1
2
3
Figure B
Figure C shows 3 spectrums coming from a heavenly body. Use
figure B to find out which element is shown by each spectrum. Write your
answer in the chart.
Element
Matching: Match the two lists. Write the correct letter on the line next to
each number.
1.
_____astronomy
A) key part of a spectroscope
2.
_____ optical telescope
3.
_____ spectroscope
C) analyzes light
4.
_____ prism
D) gathers light
5.
_____ spectrum
B) band of colors
E) study of the heavens
How a Spectroscope is Used
When a blue shift occurs
How is a spectroscope used to study light from objects in space?
1.
2.
3.
The spectroscope is connected to the telescope.
A camera is connected to the spectroscope. The camera
photographs the spectrum.
Astronomers study and identify the spectrum.
If a star is moving toward Earth, the wavelength will be smaller than if the
star were at rest relative to Earth. In this example, the light has shifted
toward the blue end of the spectrum, making what is called a blue shift.
The spectroscope does more than identify the chemical makeup of the
sun and the stars. The spectroscope tells us:
1.
2.
3.
4.
5.
The makeup of the atmosphere of the planets.
How fast a heavenly body moves and in which direction (red
shift/blue shift).
How hot a star is.
If a star is rotating.
If a star has a magnetic field
Analyzing Red Shift & Blue Shift Spectrums
When a red shift occurs
If the star is moving away from the observer, the observer sees light of a
longer wavelength than it had when it was emitted. In this case, the
observed light has made what is called a red shift.
Light can be described as traveling in the form of waves. Each color that the
human eye can see has a different wavelength. The longest visible
wavelengths are in the red end of the spectrum. The shortest visible
wavelengths are in the blue end.
Red
Orange Yellow Green
Blue
Purple
The wavelength of light that an observer sees coming from an object
depends on the motion of the object relative to the observer. If either the
object or the observer moves, the wavelength will change. The relationship
between motion and observed wavelength is called the Doppler effect.
1. An astronomer discovers two stars. Both stars appear red, but Star A
appears redder than Star B. What can the astronomer conclude?
2. If an astronaut in a spacecraft saw a star ahead that seemed to be
growing bluer as time passed, what might she assume about the motion
of the object relative to the spacecraft? List four possibilities.
Shifting Spectra & Speed
Based on the spectrums below, rank the four galaxies in order of
the speed with which they are moving away from Earth, from
slowest (1) to fastest (4).
The greater the shift the faster the object is moving towards or away from
Earth.
Spectrum
@ Rest
1. Based on Hubble’s Law, which of the
galaxies is farthest from Earth?
Galaxy
A
B
Red
2. Are any of the galaxies moving toward
Earth? Explain
C
D
Red
Red
Rank