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The Doppler EffectL

The document discusses the Doppler effect and how it relates to the redshift observed in light from distant stars and galaxies. [1] As an ambulance approaches an observer, the sound waves are compressed and the pitch is higher. As it moves away, the waves are stretched out and the pitch is lower. [2] Similarly, light from stars moving away from Earth experiences redshift, where the wavelength is stretched out and shifted to the red end of the visible spectrum. This provided evidence supporting Edwin Hubble's theory that the universe is expanding.

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intan
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844 views2 pages

The Doppler EffectL

The document discusses the Doppler effect and how it relates to the redshift observed in light from distant stars and galaxies. [1] As an ambulance approaches an observer, the sound waves are compressed and the pitch is higher. As it moves away, the waves are stretched out and the pitch is lower. [2] Similarly, light from stars moving away from Earth experiences redshift, where the wavelength is stretched out and shifted to the red end of the visible spectrum. This provided evidence supporting Edwin Hubble's theory that the universe is expanding.

Uploaded by

intan
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as DOCX, PDF, TXT or read online on Scribd
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Ambulances and the Big Bang – The Doppler Effect and Redshift (pass level)

The sound waves are The sound waves are


The ambulance is squashed up/pulled The ambulance is squashed up/pulled
The pitch of the The The pitch of the
travelling apart. travelling apart.
sound is Doppler sound is
towards us/away The wavelength towards us/away The wavelength
higher/lower Effect higher/lower
from us increases/ from us increases/
decreases decreases

1) The picture shows different wavelengths of visible light. Which colour has:

a) the longest wavelength? _____________ b) the shortest wavelength? _____________

c) the highest frequency? ______________ d) the most energy? ____________________

2) A green light is thrown towards you. Will the wavelength get longer or shorter? _________________________

3) What colour might the light look ads it gets closer to you? ___________________________________________

4) You throw the light back. What happens to the wavelength as it flies away? _____________________________

5) What colour might the light look as it flies away from you? ___________________________________________
Star number Line number
The diagram shows light collected from four stars.
Because stars are all made from the same chemicals they should
1 2 3 4 5 6 all have black lines in the same place. However, something has
happened to the black lines from stars 2, 3 and 4 to make them
1 move.

Select the right words to complete the explanation

The black lines are in the same/different places for each


2 star. The lines have moved towards the red/blue end of
the spectrum. The wavelength has got shorter/longer.
The star must be travelling towards/away from us.

3
The light from star 4 has changed the least/most. Star
4 is the furthest away star. It is moving faster/slower
than the other stars.
4
This is called redshift/nightshift.

Edwin Hubble said that if Big Bang Theory was correct, the stars should all be moving apart. He also said that the furthest stars should be moving M
away from us fastest. Describe how the changing light from stars supports his theory.

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