John Riley Holt facts for kids

John Riley Holt (born February 15, 1918 – died January 6, 2009) was an English scientist who studied physics. He played a part in developing the atom bomb. Later, he became a leader in studying tiny particles, a field called elementary particle physics.

A Young Scientist's Start

John Holt was born in Runcorn, England, in 1918. His father built boats, and his mother owned a bakery.

When he was 16, in 1934, John started studying physics at the University of Liverpool. The next year, a famous scientist named James Chadwick joined the university. Chadwick had just won the Nobel Prize in Physics for finding the neutron, a tiny part of an atom.

While John was a student, Professor Chadwick built a cyclotron at the university. A cyclotron is a special machine that speeds up tiny particles. John graduated in 1938 with top honors and won a special award called the Oliver Lodge Prize. Professor Chadwick was very impressed and took John on as a research student. He called John "the best research student he had ever supervised."

Working on Important Discoveries

During World War II, Professor Chadwick formed a team, and John Holt was part of it. They used the cyclotron to do experiments. These experiments helped confirm how much material was needed to make an atom bomb. Some of their important tests even took place in a Liverpool Underground station during air raids.

This work helped John earn his PhD degree in 1941. His research was about creating artificial radioactivity. However, his findings about uranium, which were important for the bomb, were kept secret for safety reasons. John's work was key in showing that building a nuclear weapon was possible.

After the war, John Holt became a lecturer at the University of Liverpool in 1946. He became a Professor of Experimental Physics in 1966. He helped design a bigger cyclotron. In 1949, he and C. T. Young made an important discovery about how deuteron particles behave.

Using an even more powerful machine called a synchrocyclotron, John's team studied the "weak interaction." This is one of the basic forces of nature that causes particles like the muon to decay. Their work greatly improved our understanding of the Standard Model, which describes how the universe's smallest particles work.

In the early 1960s, John helped design powerful electromagnets for a particle accelerator at Daresbury Laboratory. In 1964, he was chosen as a Fellow of the Royal Society, a very respected scientific group.

In the 1970s and 1980s, John led a team from Liverpool at CERN, a huge research center in Europe. His group studied the structure of protons. They discovered that the "spin" of a proton was not carried by its main parts, called "valence quarks," as scientists had thought before. This discovery changed previous ideas about how protons are built. John Holt retired in 1983.