Energy & Power - Overview
The Museum's collections on energy and power illuminate the role of fire, steam, wind, water, electricity, and the atom in the nation's history. The artifacts include wood-burning stoves, water turbines, and windmills, as well as steam, gas, and diesel engines. Oil-exploration and coal-mining equipment form part of these collections, along with a computer that controlled a power plant and even bubble chambers—a tool of physicists to study protons, electrons, and other charged particles.
A special strength of the collections lies in objects related to the history of electrical power, including generators, batteries, cables, transformers, and early photovoltaic cells. A group of Thomas Edison's earliest light bulbs are a precious treasure. Hundreds of other objects represent the innumerable uses of electricity, from streetlights and railway signals to microwave ovens and satellite equipment.
"Energy & Power - Overview" showing 3 items.
Sample of Plutonium-239
- Description
- The discovery of nuclear fission in uranium, announced in 1939, allowed physicists to advance with confidence in the project of creating "trans-uranic" elements - artificial ones that would lie in the periodic table beyond uranium, the last and heaviest nucleus known in nature. The technique was simply to bombard uranium with neutrons. Some of the uranium nuclei would undergo fission, newly understood phenomenon, and split violently into two pieces. In other cases, however, a uranium-238 nucleus (atomic number 92) would quietly absorb a neutron, becoming a nucleus of uranium-239, which in turn would soon give off a beta-particle and become what is now called neptunium-239 (atomic number 93). After another beta decay it would become Element 94 (now plutonium-239)
- By the end of 1940, theoretical physicists had predicted that this last substance, like uranium, would undergo fission, and therefore might be used to make a nuclear reactor or bomb. Enrico Fermi asked Emilio Segre to use the powerful new 60-inch cyclotron at the University of California at Berkeley to bombard uranium with slow neutrons and create enough plutonium-239 to test it for fission. Segre teamed up with Glenn T. Seaborg, Joseph W. Kennedy, and Arthur C. Wahl in January 1941 and set to work.
- They carried out the initial bombardment on March 3-6, then, using careful chemical techniques, isolated the tiny amount (half a microgram) of plutonium generated. They put it on a platinum disc, called "Sample A," and on March 28 bombarded it with slow neutrons to test for fission. As expected, it proved to be fissionable - even more than U-235. To allow for more accurate measurements, they purified Sample A and deposited it on another platinum disc, forming the "Sample B" here preserved. Measurements taken with it were reported in a paper submitted to the Physical Review on May 29, 1941, but kept secret until 1946. (The card in the lid of the box bears notes from a couple of months later.)
- After the summer of 1941, this particular sample was put away and almost forgotten, but the research that began with it took off in a big way. Crash programs for the production and purification of plutonium began at Berkeley and Chicago, reactors to make plutonium were built at Hanford, Washington, and by 1945 the Manhattan Project had designed and built a plutonium atomic bomb. The first one was tested on July 16, 1945 in the world's first nuclear explosion, and the next was used in earnest over Nagasaki. (The Hiroshima bomb used U-235.)
- Why is our plutonium sample in a cigar box? G.N. Lewis, a Berkeley chemist, was a great cigar smoker, and Seaborg, his assistant, made it a habit to grab his boxes as they became empty, to use for storing things. In this case, it was no doubt important to keep the plutonium undisturbed and uncontaminated, on the one hand, but also, on the other hand, to make it possible for its weak radiations to pass directly into instruments - not through the wall of some closed container. Such considerations, combined probably with an awareness of the historic importance of the sample, brought about the storage arrangement we see.
- Date made
- 1941-05-21
- Associated Date
- 1941-05-29
- referenced
- Segre, Emilio
- Seaborg, Glenn T.
- Kennedy, Joseph W.
- Wahl, Arthur C.
- Lewis, G. N.
- University of California, Berkeley
- maker
- Segre, Emilio
- Seaborg, Glenn
- ID Number
- EM*N-09384
- catalog number
- N-09384
- accession number
- 272669
- Data Source
- National Museum of American History, Kenneth E. Behring Center
Head Piece from Maiman Laser
- Description
- This object may be the first laser. It was made by Theodore Maiman and his assistant Irnee D'Haenens at Hughes Aircraft Company in May 1960.
- In 1959 Maiman attended a technical conference on the subject of lasers. Maiman heard several speakers state that ruby was unsuitable for a laser but grew troubled by some of the numbers they cited. When he returned to his lab at Hughes he began experimenting. By May 1960 he and D'Haenens constructed several small metal cylinders. Each contained a photographer's spiral-shaped, xenon flashlamp that surrounded a small cylindrical crystal of synthetic ruby. When they fired the flashlamp, the burst of light stimulated the ruby crystal to emit a tightly focused pulse of light--the first operating laser.
- Hughes Aircraft donated this and several other pieces of Maiman's apparatus to the Smithsonian in 1970. The crystal mounted inside is from a 1961 experiment. While the donation records indicate that this is the first laser, Maiman wrote that he received the first laser as a gift when he left the company in April 1961. Several experimental models were made during the research, a common practice. So we may never know which unit actually generated the first laser light.
- Location
- Currently not on view
- Date made
- 1960
- associated date
- 1960
- maker
- Maiman, Theodore H.
- Hughes Aircraft Company
- ID Number
- EM*330050
- accession number
- 288813
- catalog number
- 330050
- Data Source
- National Museum of American History, Kenneth E. Behring Center
Wave guide with ruby crystal
- Description
- This is an experimental device made by Theodore Maiman at Hughes Aircraft in late 1959 or early 1960 as part of the series of experiments leading up to the demonstration of the first laser in May 1960. This object features a cube-shaped ruby crystal mounted at one end of a microwave wave-guide. Maiman sought to test the response of the synthetic ruby crystal to microwave stimulation. Other researchers claimed that ruby would be a poor material to use in a laser. Maiman thought otherwise.
- After Charles Townes invented the microwave-emitting maser in 1954, researchers began trying to move to the higher energy levels of infrared and visible light. They referred to such devices as "optical masers," and only later did people adopt Gordon Gould's term, "laser." This experimental piece clearly shows the influence of microwave technology. The metal tube is not a stand but rather a hollow guide that channels microwaves to the ruby crystal. The results of this and other experiments led Maiman to ultimately choose a cylinder of ruby rather than a cube for his laser.
- Location
- Currently not on view
- date made
- 1959
- associated date
- 1960
- associated user
- unknown
- associated institution
- Hughes Research Laboratories
- maker
- Maiman, Theodore H.
- Hughes Aircraft Company
- ID Number
- EM*330052
- accession number
- 288813
- catalog number
- 330052
- Data Source
- National Museum of American History, Kenneth E. Behring Center