Henry Way Kendall

Henry Way Kendall (1926-1999), American physicist and Nobel Prize winner. Kendall and his two colleagues, Canadian physicist Richard Edward Taylor and American physicist Jerome Isaac Friedman, discovered the quark, one of the fundamental building blocks of matter. For this discovery, they shared the 1990 Nobel Prize in physics.

Kendall was educated at Amherst College and the Massachusetts Institute of Technology (MIT), where he received his Ph.D. degree in 1954. After two years of postdoctoral research, he joined the faculty at Stanford University. Kendall returned to MIT in 1961, remaining on the faculty there throughout the rest of his career.

Protons and neutrons, found in the atom's nucleus, were once thought to be the elementary particles of matter. In the 1950s physicists began to search for more elementary particles, and in 1964 two scientists independently predicted the existence of a subatomic particle now called the quark. But no one had proof that they actually existed. Using a new and powerful particle accelerator at the Stanford Linear Accelerator Center (SLAC), Kendall and his colleagues devised an experiment in the late 1960s to study protons by colliding electrons into them. The researchers expected the electrons to pass through the protons or to bounce off them, which they did at first. By speeding up the electrons so they were traveling at close to the speed of light, the scientists made a remarkable observation. Many of the electrons rebounded at odd angles, which was a completely unexpected result. Particles within the protons apparently were causing this unexpected electron behavior. Additional experiments confirmed the suspicion that those particles were quarks.

Six different types of quarks have since been found and have been given the names up, down, charm, strange, truth, and beauty. Scientists have renewed their studies on other types of atomic particles, which are believed to be made up of quarks. They have also used this discovery to try to understand the formation of all known matter during the big bang, the theoretic gigantic explosion that led to the creation of the universe billions of years ago.