Edwin McMillan

Edwin was a scientist.

He loved to study how things work. He found a new part of nature.

He hit uranium with tiny bits of light. This helped him find a new element. He named it neptunium. It was named after a planet.

This big discovery won him a prize. He shared the prize with a friend. He was a very important leader. He helped many people learn about science.

Edwin McMillan was a famous American physicist.

He spent his life studying the tiny parts of our world.

One of his biggest wins was finding a new element. An element is a basic type of matter. He found neptunium. He found it by hitting uranium with tiny particles. He worked with a scientist named Philip Abelson to prove it was real. They named it after the planet Neptune. This big discovery won him the Nobel Prize in Chemistry in 1951.

During World War II, Edwin did very important work. He helped build the Los Alamos Laboratory. This was a place where people designed atomic bombs. He led teams that worked on different ways to build these weapons. He also worked on radar and sonar. Radar uses radio waves to find things in the air. Sonar uses sound to find things under the water.

Later, Edwin became the director of a big science lab. He led the Berkeley Radiation Laboratory for many years. He was a great leader who helped many other scientists.

Edwin McMillan was a famous American physicist.

He spent his life studying the tiny parts of the physical world. He was born on September 18, 1907, in Redondo Beach, California. His father was a doctor, and many of his relatives were doctors too. McMillan grew up in Pasadena and went to school there for many years. He later studied at the California Institute of Technology and Princeton University. He earned his doctorate from Princeton in 1933. This training helped him become a leader in science.

One of his greatest wins was finding a new element. An element is a basic type of matter. McMillan found neptunium by hitting uranium with tiny particles called neutrons. He used a machine called a cyclotron to do this. He worked with a scientist named Philip Abelson to prove the discovery was real. They noticed the new substance behaved differently than any known element. They named it neptunium after the planet Neptune. This was because uranium is named after the planet Uranus.

This big discovery won him the Nobel Prize in Chemistry in 1951.

During World War II, McMillan did very important work for his country. He joined the Manhattan Project in 1942. This was a wartime effort to create atomic bombs. He helped set up the Los Alamos Laboratory in New Mexico. He worked with Robert Oppenheimer to plan the new buildings there. McMillan led teams working on different ways to build these weapons. One way was called the gun-type design. Another way used a method called implosion.

McMillan also worked on ways to see things that are hidden. He worked on microwave radar at the MIT Radiation Laboratory. Radar uses radio waves to find objects in the air. In 1941, he helped show that radar could find a submarine under the water. Later, he worked on sonar at the Navy Radio and Sound Laboratory. Sonar uses sound to find things under the water. He even made a special device to help sailors train with sonar. This work helped people understand the world around them much better.

After the war, McMillan returned to the Berkeley Radiation Laboratory. He had worked there since 1933 with Ernest Lawrence. He helped build machines called synchrotrons. A synchrotron is a large machine used in science. He became the director of the laboratory in 1960. He stayed in that role until he retired in 1973.

His life shows how studying small things can change our whole world.

Edwin Mattison McMillan was a prominent American physicist.

He is best known for being the first scientist to produce a transuranium element. This means he found an element that exists beyond uranium on the periodic table. For this massive achievement, he shared the 1951 Nobel Prize in Chemistry with Glenn Seaborg. McMillan's life was defined by his work with radiation and the tiny building blocks of matter. He spent much of his career at the Berkeley Radiation Laboratory. He even served as its director from 1960 until his retirement in 1973.

McMillan's scientific journey began with rigorous academic training. He was born in Redondo Beach, California, on September 18, 1907. He later attended the California Institute of Technology, where he worked with the famous chemist Linus Pauling. He earned his Doctor of Philosophy from Princeton University in 1933. His doctoral research focused on the deflection of molecules in electric fields. After finishing his degree, he joined Ernest Lawrence at the Berkeley Radiation Laboratory. At Berkeley, he became an expert in using the cyclotron. This machine uses magnetic fields to accelerate particles for scientific experiments.

One of McMillan's early successes involved the discovery of new isotopes. In 1935, he worked with M. Stanley Livingston to find oxygen-15. They produced this isotope by bombarding nitrogen gas with deuterons. They then mixed the result with hydrogen and oxygen to create water. By using calcium chloride to collect the water, they found concentrated radioactivity. This proved the radioactivity was inside the oxygen. Later, in 1940, he and Samuel Ruben discovered the isotope beryllium-10. This was a difficult discovery because beryllium-10 has a very long half-life of about 1.39 million years.

McMillan's most famous discovery was the element neptunium. In 1939, he began experimenting with uranium by bombarding it with neutrons. He used a cyclotron to produce these neutrons by hitting beryllium with deuterons. He detected a radioactive isotope with a half-life of about 2.3 days. He suspected this was a new element with an atomic number of 93. Initially, he and Emilio Segrè thought it might be like the element rhenium. However, they realized their first chemical tests were not rigorous enough. They decided to try a new reaction using hydrogen fluoride with a reducing agent.

This new method worked and proved the substance was not a rare-earth element. McMillan then collaborated with Philip Abelson, who had been working on the same problem. Together, they showed that the 2.3-day isotope increased as a 23-minute isotope decreased. This specific decay chain proved the existence of a new element. They published their findings in the journal Physical Review on May 27, 1940. They named the element neptunium. This name follows the pattern of uranium, which is named after the planet Uranus. Neptune is the next planet in the solar system beyond Uranus.

During World War II, McMillan's work shifted toward military technology. He worked at the MIT Radiation Laboratory on microwave radar. In 1941, he helped demonstrate that radar could detect a submarine's conning tower. He also worked on sonar at the Navy Radio and Sound Laboratory. He developed a patented sonar training device for submariners. In 1942, he joined the Manhattan Project under Robert Oppenheimer. He helped establish the Los Alamos Laboratory in New Mexico. He worked on the design of different nuclear weapons during this time.

At Los Alamos, McMillan held leadership roles in weapon design. He served as the deputy head of the gun-type nuclear weapon effort. This design, codenamed "Thin Man," required a very high muzzle velocity. He also studied the development of implosion-type weapons. This method used explosive lenses to compress a core. McMillan helped organize the technical buildings and recruited many famous scientists. After the war, he returned to Berkeley to build synchrotrons. A synchrotron is a large particle accelerator. His career bridged the gap between fundamental physics and major global events.