The Discovery of Atmospheric Pressure

Demos to Perform:
Air has mass--  1g/liter
Barometer-- air pushes Hg up 760mm & H2O up 10 meters.
The pressure is 1kg/cm2, or 101 kpa.
The Force Pump to give pressure.
The Brass Aspirator
The Manometer--
   Open Tube & Closed Tube
The Bourdon Gauge--
The Magdeburg Hemispheres--
Crush the can
No crush the 4-liter jug.
The Mysterious Siphon


Fearing an attack by foul foe, the Duke of Tuscany has
his pump moved up inside the walls of his castle.

... but, oohh, ooohh, the water will only rise up ten meters!



Torricelli does his demos for the
Grand Duke of Tuscany

And informs the duke that the pump must go back within
ten meters of the water level.


The Force Pump is placed in the bottom of the well
and it pushes water up to any desired height.
It is independent of atmospheric pressure.

Firemen Blast Cat from Tree with the Big Hose.

And still the pump must be within ten meters of the water
so that atmospheric pressure can push the water to the pump.

Atmospheric Pressure PUSHES, not sucks!

The pumps of Boomeria operate the battle towers and

The Aqua Goose !

Atmospheric Pressure is 1 kg/cm2. This will push water to a height of 10 meters, and mercury to a height of 76 cm. The Total Force on an evacuated container = pressure X area. So a large steel barrel will have an enormous, crushing, total force on it, Video:


The total force to separate the hemispheres is
pressure times area!

The Magdeburg Hemispheres demonstration, Video:

Atmospheric pressure causes a large total force on a guy who is pushed out of an airplane window, Video:



Barometers for measuring Atmospheric Pressure


A larger surface area on the outer edge of the tube gives a greater total force. Hence the tendency to straighten out and move the pointer.

Bourdon Gauges at Boomeria

Main Machinery Spaces at Boomeria
control big action!



Demonstration and History of "The Crapper". Sanitation in Space. Video:

AWESOME Graphics of The Experiments of Torricelli at the

The Art of Experimentation in the Accademia Galileiana del Cimento (1657-1667)

Here Endeth Atmospheric Pressure