# Light by yurtgc548

VIEWS: 6 PAGES: 10

• pg 1
```									Speed of light
A race to compare the speed of
light to other things
   A quick comparison of how far things can
go in 1 second.
Start
Fastest Athletes         10 m
Cheetah                             25 m
Fastball                             45 m
Drag racer
Bullet
Supersonic Jet
Crack of thunder
Flash of lightning
Most are still going
We will continue these throughout the presentation!
They are roughly to scale.
Drag Racer                          175 m

Bullet (still going)

Supersonic Jet (still going)

Crack of thunder

Flash of lightning
Astronomical Distances
   Light takes 8 minutes to get from the Sun to the
Earth.
   It takes 4 years to get here from the next nearest
star aside from the sun, Proxima Centauri which
is 4 light years away.
   Light year-The distance light travels in one year
   9.5 x1015 m (a really big distance)
Space travel problems

   Since we can’t even get close to the speed
of light deep space travel would take
extreme amounts of time.

crack of thunder (340 m)
Looking into the past
   Every time you look at the stars you are
looking at the distant past.
   If you see a star that was 100 light years
away blow up (supernova) it actually blew
up 100 years ago.
   It just took the light that long to get to you.
Speed of light in things other
than a vacuum
   Whenever light hits a medium it slows it
down.
   The more dense the material the slower
light can travel.
   Therefore light tends to travel faster in a
gas, and slowest in a solid.
   It travels fastest in a vacuum (nothing)
Speed of light in different
substances
Vacuum    2.99792458 x 108 m/s
Air       2.9970 x 108 m/s
Water     2.26 x 108 m/s
Glass     1.97 x 108 m/s
Diamond   1.24 x 108 m/s

Bullet (780 m)
It may slow down but…
   It is still unbelievably fast compared to
everything else.
   You can not travel faster than the speed of
light. Several interesting things happen
when you get close.

Supersonic Jet (900 m)
How far will that light go

If I had 15,000 more slides just like this one, I could cover the
distance light would travel (300,000,000 m)

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