the universe
TRANSCRIPT
The Universe
http://science.howstuffworks.com/big-bang-theory1.htm
How do we know what happened billions of years ago?
• Scientific theories are usually formed when someone makes observations and then forms conclusions about what he/she sees.
What’s happening? (observe)
The kitchen is messy with spilled flour and sugar, the oven is warm, candles are scattered
around the floor.
Detectives are Scientists
• They make observations about:– Evidence at the
scene– Prints left behind– Motive or reasons– DNA collected
…and form conclusions.
• They may not have witnessed the crime, but they can make an educated guess about what happened.
You weren’t there, but you can make an educated guess based on
your observations.Which direction is the bullet moving?
To the left?
To the right?
Astronomers (people who study space) are detectives
• They study and observe the universe and then form conclusions about out how it probably formed.
So how did our universe form?
• Using telescopes, spectroscopes, and other instruments, scientists have made the following observations….
Galaxies are spreading farther and farther apart
If we work backwards, then 13.7
billion years ago, all matter use to be
all together
How do we know if stars are moving towards Earth or away?
• The Doppler effect• Chime demo• Sound waves move differently when they come
towards you or move away from you.
https://www.youtube.com/watch?v=imoxDcn2SgoDoppler effect sirenhttps://www.youtube.com/watch?v=a3RfULw7aAY&feature=relatedDoppler effect car horn
Light waves from stars also show a difference when they move.
• Use a spectroscope
• Red shift = moving away from you
• Blue shift = moving towards you
Astronomers use these observations to conclude that the whole universe must have
been all together at one point about 13.7 billion years ago.
1. 13.7 billion years ago, all matter (stuff you can touch) was
together in a very small ball, then it exploded. Parts of atoms
floated around the universe.
2. One billion years later, atoms formed and large clouds of
hydrogen (H) and helium (He) were pulled together due to gravity and galaxies formed.
3. H and He crashed into each other creating light and heat
(through nuclear reactions) and stars formed.
Think about the universe being like a balloon-spots on the balloon get farther and
farther apart as it expands
5. The universe will stop expanding and gravity will pull it back into a ball
and then the big bang will happen again.
http://teachertube.com/viewVideo.php?video_id=73929&title=Big_BangHistory Channel Big Bang 3min
https://www.youtube.com/watch?v=OdsWhHWdc1g&feature=player_embedded#%21The Big Bang demonstrated by a college band
How big is the Universe?https://www.youtube.com/watch?v=5NU2t5zlxQQ&feature=player_embedded
Big Bang Theme Songhttp://www.youtube.com/watch?v=lhTSfOZUNLo