- How in the world did the Inquisition lead to the invention
of the vacuum pump
and what does that have to do with electricity?
Well, I'll tell you, and along the way,
I'll talk about heavy air and the patient duke,
a freaked out Galileo, unfortunate facial hair,
an impressive demonstration with 24 horses,
and a really stupid demonstration involving a stinky ball
and a stick.
Ready? Let's go.
♪ Electricity, electricity ♪
This story begins in 1633,
when a 70 year old Galileo is in serious trouble.
The religious leaders in Rome were very upset with him
for saying the earth circles, the sun,
and therefore is not the center of the universe.
In fact, he had to prostate himself
in front of the Inquisitor's general
to denounce the heresy of having held that the sun
is the center of the world.
Unable to study the stars,
Galileo decides collect the last 30 years
of non-planetary physics,
and publish it as a book.
The religious leaders in Rome didn't know it,
but this would be more revolutionary,
and dare I say it, heretical.
Galileo did experiments on motion.
Think of him dropping balls off the side
of the tower of Pisa.
And he started to think about air resistance,
and then he started to think about air.
What was it and did it have a weight?
Galileo decided to solve this problem directly
by actually measuring the weight of air on the scale.
He took a bottle with a straw and a valve in it,
and he waited on a balanced scale.
Then he pumped in the extra air
and the bottle weighed a few grams of sand more.
When he released the air,
it weighed a few grams of sand less.
So air weighs something,
but how much compared to say water?
He then filled the same bottle
three quarters of the way with water
without letting any of the air escape.
So the air gets smushed, and he weighed it.
Then he released the air and weighed it again.
By assuming that the volume of air that escaped was
about the same as the volume of water he put in there,
he got the air is about 400 times lighter than water.
That doesn't sound like much, does it?
And it isn't much for a bottle.
However, think about the weight of air in a big building,
say the Parthenon in Rome.
Imagine you took all the air from inside the Parthenon
and measured it on the scale.
How much would just the air weight,
1 pound, 10 pounds, a hundred pounds?
Just the air in that building weighs over, ready,
150,000 pounds, which is crazy,
and caused Galileo to panic.
He decided that air in a bottle has weight,
but once you release it, it's weightless.
This is a mistake and a doozy.
Seeing 1630, the grand duke of Florence was trying
to pump water uphill.
But all of the pumps conked out at about 33 feet
and no one knew why.
Well, it turned out Galileo had the solution
and it all had to do with that heavy air.
Three months before he died,
Galileo hired a brilliant assistant with a stupidly
oversize, mustache and goatee,
and the lyrical name of Evangelista Torricelli.
Torricelli ignored Galileo's freak out
about the weightless air.
He thought air was always pushing on us,
but in every direction so we never know the state.
In fact, he said, "We live submerged
at the bottom of an ocean of air."
Torricelli decided the reason suction pumps work
is not because the suction pulls,
but because the air pushes
and the vacuum does not push back.
In 1644, Torricelli came up with an experiment
with mercury to demonstrate air pressure.
He used mercury instead of water
because it is 13 times more dense than water.
And if water can make a column 33 foot tall,
mercury only makes us column 2.5 feet tall,
which is a much more manageable size.
Torricelli took a three foot long tube,
and filled it with mercury,
covered the end and upended it
into another container of mercury.
He then removed the cover
and a half a foot of mercury fell out of the tube,
leaving a gap at the top full of nothing,
as no air could get in.
Torricelli had made a vacuum without suction,
and he made a device of magical properties
with a column of mercury suspended against gravity.
The air is pressing on the mercury in the cup,
but nothing is pushing back at the top of the tube.
So the air is what's holding the mercury in place.
In fact, air pressure can change if you change altitude,
or if a storm is about to start.
And when that happens,
the height of the mercury also changes,
which is why pressure is often measured in mmHg,
for millimeters of mercury
or in torr, named after our fella Torricelli.
Also the device he invented is called a barometer
for pressure meter.
And now we get
to a German politician named Otto von Guericke.
Guericke was actually the first person
to think of using Torricelli tube to predict storms,
which makes him the father of meteorology.
But he was particularly interested in the vacuum on the top.
He wondered if instead of having gravity remove a bit
of liquid and create a vacuum,
if he could just use a water pump
and create a vacuum that way.
Sometime in late 1640s,
Guericke filled a wooden casket with water,
closed and sealed it,
and then remove the water with a pump he borrowed
from the fire brigade.
Unfortunately, the air just seeped in through the wood.
He then tried it with a metal container,
and the metal container promptly imploded.
Finally, he created two 20 inch diameter,
extra thick copper hemispheres
that he fit together in a sphere and it worked.
Still, he was frustrated
because no matter how hard he tried,
he couldn't remove all the water.
In 1650, he had a thought:
did he need water at all?
He then modified his pump to remove air, instead of water.
Guericke invented a device that was basically a piston
in a cylinder with two valves.
When he pulled on the piston,
the air expanded into the cylinder.
When he pushed on the piston,
the air flowed into the atmosphere.
Now, when he used his pump,
the sphere stuck together like super glue.
But as soon as the air was let in, they would fall apart.
Just like Torricelli,
Guericke was demonstrating the power of air.
See, when he removed the air from inside the sphere,
the air on the outside was still pressing,
but nothing was pressing back on the inside.
Therefore, in order to separate the hemispheres,
you had to add as much force as the air has.
This is a surprisingly large force.
Guericke began doing impressive demonstrations
with strong men playing tug of war on the sphere.
He even up the WOW factor with two teams of horses,
dramatically pulling on the hemisphere.
You might wonder what this has to do with electricity.
Well, that's coming.
See, despite the fact
that the vacuum pump was a practical device,
and vital for the development of the combustion engine,
Guericke wasn't interested in practicality.
He was interested in theory.
See, he like Galileo before him,
believed the Earth circled around the sun.
He also believed that space was full of nothing
or space is a vacuum.
He built the vacuum pump to prove the vacuums can exist.
Therefore Guericke had experiments
and theories to show the vacuum of space
and he had experiments and theories
to demonstrate the air that we all swim in.
What he was missing was an experiment for the Earth.
And that's where he came up with a very strange idea.
He modeled the Earth with a ball of stinky sulfur
on the stick,
and he modeled gravity with static electricity.
Guericke never said why he used sulfur.
It's really hard to work with,
and it smells like rotten eggs.
The only thing I can think of
is that volcanoes sometimes smell sulfuric
so maybe he thought that's why it was good model
for the Earth.
Anyway, he rubbed his Earth
and picked up leaves and feathers.
By the way,
this is a ridiculous theory and has no relationship
to how gravity actually works.
However, for all his smelly play acting,
Guericke figured out something new about electricity.
He detected that after a while,
the small objects fell off the sphere.
Moreover, they didn't just fall off,
they repel off the sphere,
eand can be chased around the room.
In other words,
electrics can repel as well as attract.
Guericke's book was very popular,
and inspired the study of vacuums in Europe.
His work on his wonderful globe, however,
were mostly ignored, probably because it was ridiculous.
However, most people in Europe knew that electrics
could repel because of him.
It was actually Guericke's work on vacuums
that inspired the next breakthrough in electricity.
A shaken barometer,
steered Isaac Newton's poor, abused assistant
to create the first fluorescent lamp
almost a hundred years before the invention of the battery.
And well over 200 years
before the invention
of the first commercial fluorescent light bulb.
And that story is next time
on the secret history of electricity.
♪ Electricity, electricity ♪
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