Lecture 4
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World War II
Bombing Technique Developments
Technological Escalation in WW II
The Beginning of the Nuclear Age
World War II (1939-1945)
- 1940-41: Battle for Britain
Civilian population targeted - 1941-1944: Allied Bombing Campaign: Incendiary bombs, Carpet bombing, and Artificial firestorms (~1000 planes/ several tons of bombs each)
Bombing Technique Developments
- Firestorm Technique
This was achieved by dropping incendiary bombs, filled with highly combustible chemicals such as magnesium, phosphorus or petroleum jelly (napalm), in clusters over a specific target. After the area caught fire, the air above the bombed area, become extremely hot and rose rapidly. Cold air then rushed in at ground level from the outside and people were sucked into the fire. Such fire storms developed winds up to 300 mph and air temperatures estimated at 1,000 degrees. - Fire storms create the Stack (chimney) Effect in thermodynamics.
(see equation on right)
v = wind velocity in m/s
g = 9.8 m/s2 earth acceleration
H = height of heat column in [m]
To = outside temperature, K
Ti = inside temperature in K
For typical firestorm:
H ≈ 1000-2000 m
Ti ≈ 1300 K
To ≈ 300 K
V ≈ 98m/s = 220 miles/h. Recall that hurricane speeds ~ 100
miles/h
Technological Escalation in WW II
Technological escalation during World War II was more profound than in any other period in human history. More new inventions, certainly as measured by such means as patent applications for dual-use technology and weapon contracts issued to private contractors, were deployed to the task of killing humans more effectively, and to a much lesser degree, that of avoiding being killed. Unlike technological escalation during World War I, it was generally believed that speed and firepower, not defenses or entrenchments, would bring the war to a quicker end. Second goal was to weaken enemy morale by direct attacks on the civil population designed for maximizing devastation.
The Beginning of the Nuclear Age
American and British nuclear physicists felt they needed to start an A-bomb project to avoid falling behind their German counterparts. They feared Hitler's forces would be the first to have use of atomic arms. This evaluation was based on a number of considerations:
- The pre-war stop of uranium export.
- The high caliber of German theoretical and experimental physicists like Otto Hahn, Paul Harteck, Werner Heisenberg, Fritz Strassmann, and Carl-Friedrich von Weizsäcker
- German control of Europe's only uranium mine after the conquest of Czechoslovakia;
- German capture of the world's largest supply of imported uranium with the fall of Belgium;
- German possession of Europe's only cyclotron with the fall of France;
- German control of the world's only commercial source of heavy water after its occupation of Norway.
