The theory that originally, all matter in the universe was concentrated at a single tiny point. This then began to enlarge rapidly in a hot explosion-the Big Bang-and it is still expanding today,
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When a siren on a police car is stationary, what are the sound waves like that reach two people on opposite ends of the car?
The sound waves travel equally in all directions so both people hear the same frequency of wave,
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AS the police car and siren move towards one person, what are the sound waves like and what is heard?
As the police car moves forward, the sound waves in front becone bunched together, creating a shorter frequency so a higher pitch,
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S the police car and siren moves away from one person, what are the sound waves like and what is heard?
As the police car moves away, the waves behind the car stretch out and have a longer frequency so a lower pitch,
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using a spectrum, how do we know the sun contains helium?
As there are black lines of the spectrum of the light from the sun where the helium hasd absorberd the light
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When looking at a spectrum of a distant star, where are the black lines moving towards and why?
The red end of the spectrum due to the Doppler effect-their frequency has dcreased,
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The further a star is from us, thw more its light is red shifted? What does this tell us?
It tells us that distant galaxies are moving away from us and that further away galazies are moving faster away.
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What have scientists disovered being emitted from all directions in space and what does this show?
Cosmic microwave background radiation-This was created at the beginning of the universe so supports theory,
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Other cards in this set
Card 2
Front
When a siren on a police car is stationary, what are the sound waves like that reach two people on opposite ends of the car?
Back
The sound waves travel equally in all directions so both people hear the same frequency of wave,
Card 3
Front
AS the police car and siren move towards one person, what are the sound waves like and what is heard?
Back
Card 4
Front
S the police car and siren moves away from one person, what are the sound waves like and what is heard?
Back
Card 5
Front
using a spectrum, how do we know the sun contains helium?
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