Word: vapor
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Dates: during 1930-1939
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Mechanical pumps have a certain limit beyond which they cannot decrease the vacuum chamber pressure any further. So Dr. Hickman has designed a sort of chemical pump which goes to work after the mechanical pump has done its best. A spray of oil vapor is shot in one side of the chamber, out the other. Some of the gas molecules roaming inside are struck by the oil particles, adhere to them, are thus escorted outside through the oil vapor exit...
...Wilson invented the cloud chamber. This device makes visible the fantastically rapid paths, straight, curved, or broken, of electrons and other subatomic particles. The cloud chamber contains water vapor or other fluid vapor which, suddenly expanded by a piston, condenses along the particle paths in fog droplets that show up in photographs as white streaks...
...cooling magnetic salts closer to absolute zero than had previously been done. His method makes use of the principle that magnetization heats matter, demagnetization chills it. After preliminary cooling with liquid helium, the salt is magnetized, the heat thus generated drawn off into a jacket filled with helium vapor; then demagnetization pushes the substance down one notch further into the cold. By repetitions of this cycle, Dr. Giauque (pronounced gee-oke) has reached one-tenth of one degree above absolute zero. This is the U. S. cryogenic record. Since no imaginable thermometer could record such cold, it is calculated...
Lately Dr. Anderson and his lean young coworker, Dr. Seth Neddermeyer, have been trying to trap barytrons near the end of their ranges-that is, as they slow up from exhaustion of energy after many collisions. The two physicists have a "cloud chamber" filled with argon, helium and alcohol vapor. A particle passing through knocks ions (electrified fragments) out of the gas atoms, and the vapor condenses on the ions, making a visible track which shows up as a white line in photographs. A device called a coincidence circuit snaps the picture when the particle passes through...
...current Physical Review Dr. Street undertakes to answer the mass question-approximately, not exactly. He took 1,000 photographs of cosmic ray activity in a "cloud chamber," an apparatus in which water vapor condenses in the path of ionizing particles as droplets of fog which can be photographed. Dr. Street rigged his apparatus so that the condensing value would operate not instantly when an ionizing particle passed through, but one second later. This allowed the fog tracks to spread a little, enabling him to get a better count of the droplets...