Transcript Archimedes and the Crown

Archimedes and the Crown
A Genius in the Tub
Who is Archimedes?
Archimedes was a Greek philosopher and
mathematician
Archimedes
(287-212 B.C.)
he lived more than 2,000 years ago
Why do we still talk about
him?
• he is still known as one of the greatest physical
scientists of all time.
This is a story about one of his
most famous discoveries.
It is so famous it is called:
The Archimedes Principle
Archimedes lived more than 2000 years ago
in a Greek city called Syracuse.
There he is: Archimedes
• He was very good at inventing things and figuring
out how things work.
• Archimedes was so smart that the king of the roots
crew, Tubby, needed his help many times.
• Once King Tubbby had a goldsmith make
him a new crown.
• He gave the goldsmith lots of gold to make
a big beautiful crown.
• The goldsmith made King Tubby a crown
shaped like a beautiful ring of gold leaves,
just like the Korean Bird Feather Crown
• But King Tubby told Archimedes that he
was worried. He did not trust the goldsmith
who lived strictly for the money.
The goldsmith may want to keep some of
the gold for himself and mix something else
with the rest of the gold to trick the king
and pocket the extra gold.
King Tubby had a beautiful new gold
crown, but was it really all gold? He
wondered and wondered…
He could find out by having the crown
melted to see what it was made of, but then
he would have to remake the crown.
And if he paid the goldsmith again would
he steal some of the gold the second
time he made the crown? Who knows.
The king knew that he needed someone
clever like Archimedes to help him.
Archimedes wanted to help King Tubby. He
felt that the King should have a real gold
crown since the King spreads peace across
the lands!
• AND, if the goldsmith was a thief, a cheat,
the King will lock him up in jail to
reeducate him!
But how could Archimedes find out if
the crown was real without ruining the
crown?
?????
• That night, Archimedes wanted to take a
bath. While filling the tub, Archimedes was
so busy thinking about the crown that he
filled the tub with too much water.
Archimedes got into the tub and water
spilled all over the floor!
Archimedes wondered why the water spilled out
when he got into the tub.
He realized that there wasn't enough room in the
tub for him and all that water!
So how much water will spill out if he
puts something in the tub? Archimedes
took his bath toys and did some
experiments.
The bigger something was, the more
water spilled. So even if a bath toy had
a unusual shape, he could tell how big
it was by how much water spilled out.
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Archimedes noticed that some things that
were big were very light and floated. But
some things that were small were very
heavy and sank.
• Archimedes called how heavy something is
(mass) compared to how big it is (volume)
the density. Different materials all have
different densities.
Story Break
Tech Demo: Determining Density
[email protected] - kippdynasty - nationtime. Density at 0 4.7 and 10
Little things like rocks had more density
and sank. But his big toy alligator had less
density and floated.
Archimedes could put the crown into the
tub to find the density of the crown, telling
him if the crown was made of gold or
something else.
Now Archimedes knew how to find out if
the crown was real gold. He was so excited
he shouted "Eureka!", which is Greek for "I
found it!"
He got up and went running through
the streets in a white towel shouting
"Eureka! Eureka! Eureka!"
Archimedes was so excited that when he got
out of the bath he forgot to put on his clothes,
keeping it real with his indigenous style!
Archimedes ran to King Tubby and announced
that he could figure out if the crown was really
made of gold. King Tubby said "That's great, but
first put on some clothes!"
• We now call his discovery The Archimedes
Principle, which states that an object placed
in a fluid has a buoyant force upward equal
in weight to the fluid displaced (pushed out
of the way) by the object.
Ticket to Leave
1.
When you fart underwater what gets released?
2.
Are the gas bubbles more dense or less dense than water?
3.
Draw a picture and diagram of the forces at work.