Kind: captions
Language: en
[Applause]
imagine you're in a space suit drifting
away from the Sun rather than dwell on
how you ended up here open the P bay
doors how I'm sorry Derek I'm afraid I
can't do that you decide to collect data
for your Google science fair project you
notice that as you move further away
from the Sun the intensity of its light
decreases and this isn't due to the
light dying away or being absorbed it's
simply due to the light energy being
spread over more space consider the
light emitted by the sun in a single
second it's enough energy to power the
whole world for a million years or to
heat up 3,200 billion billion hot
pockets as all that light travels out
through space you can think of it
spreading out over the surface of a
growing sphere and since the surface
area of a sphere is 4 pi r s the
intensity of light is inversely
proportional to the square of distance
from the Sun so when you're twice as far
away as where you started the light will
be a quarter as bright and this is known
as the inverse Square law so as you
continue past the Pluto formerly known
as a planet the light becomes dimmer and
dimmer until it is so faint that you
can't even see the sun well that's not
terribly surprising but what if you had
really sensitive eyes like the eyes of a
frog well then as you move further away
from the Sun by The in ver Square law
you would expect to see the light
decreasing in brightness but never
fading out completely but that is not
what you see at some point the sun
begins to flicker so you see flashes of
light separated by complete darkness and
what's weirder as you continue to move
further away the flashes would not
decrease in brightness instead they
merely become less frequent if you took
the average of the flashes in darkness
you would find it smoothly follows the
curve of the inverse Square law but the
light itself comes in lumps they are
indivisible and so they can't get any
less intense only more spread out this
dramatically demonstrates that light is
quantized meaning it always comes in
multiples of a smallest quantity called
a
Quantum is that incredible you're making
the slit narrower and yet the spot on
the wall is getting wider the narrower
you make it the wider that spot on the
wall
becomes to understand this we have to
look at Heisenberg's uncertainty
principle can you think of some other
things that are quantized please put
them in the comments and say what a
single Quantum of that thing is I'm
sorry Derek I'm afraid I can't do that
for example cash money is quantized and
a Quantum of money is a penny unless you
live in Australia in which case we've
got rid of pennies so the smallest
division is 5 cents but now a lot of
machines won't even take 5 cents so we
should probably get rid of that too okay
what other things can you think of