Edmund Clifton Stoner facts for kids

Edmund Clifton Stoner (born November 2, 1899 – died December 27, 1968) was a British physicist. He was a scientist who studied how things work in the universe. He is best known for his important work on ferromagnetism. This is the science behind why certain metals, like iron, cobalt, and nickel, are magnetic.

Stoner also helped us understand how electrons are arranged in the periodic table. He even figured out a special limit for how big a dying star can be, called the Chandrasekhar limit.

About Edmund Stoner

Edmund Stoner was born in Esher, Surrey, England. His father, Arthur Hallett Stoner, was a famous cricketer. Edmund was a very smart student. He won a scholarship to Bolton School, where he studied from 1911 to 1918.

After school, he went to the University of Cambridge in 1918. He finished his studies there in 1921. After graduating, he worked at the Cavendish Laboratory. There, he studied how X-rays are absorbed by different materials. He also looked at the energy levels of electrons.

In 1924, Stoner wrote a paper about his findings. This paper was very important. It helped set the stage for a big idea in physics called the Pauli exclusion principle. This principle explains how electrons behave in atoms.

In 1932, Stoner became a Lecturer at the University of Leeds. He worked in the Department of Physics. By 1939, he became a Professor of Theoretical Physics. From 1951 to 1963, he held a very important position called the Cavendish Chair of Physics. He retired from his work in 1963.

Stoner's Work on Stars

Edmund Stoner also did some early work in astrophysics. This is the study of stars and space. He calculated something very important about white dwarf stars. A white dwarf is what's left of a star after it has used up all its fuel.

In 1931, Stoner figured out the maximum mass a white dwarf can have. This is known as the Chandrasekhar limit. If a star is heavier than this limit, it cannot become a white dwarf. It will collapse into something else, like a neutron star or a black hole.

Stoner made this discovery a year before another famous physicist, Subrahmanyan Chandrasekhar, did. Stoner's calculations were based on earlier work by Wilhelm Anderson and Ralph H. Fowler.

In 1932, Stoner also created equations that describe the pressure and density inside stars. These equations help scientists understand how stars work. Another physicist, Yakov Frenkel, had published similar work earlier.

Understanding Magnetism: The Stoner Model

A diagram showing how electron spins can split in the Stoner model. This splitting helps explain why some materials are magnetic.

One of Stoner's most famous contributions is his work on ferromagnetism. This is the type of magnetism you see in everyday magnets, like those made of iron. Stoner developed a theory called the "collective electron theory of ferromagnetism."

In simple terms, Stoner's model explains how electrons in a material can make it magnetic. Electrons have a property called "spin." You can think of it like a tiny magnet spinning in one direction or another.

Stoner's idea was that in some materials, the electrons' spins can naturally line up. When many electron spins point in the same direction, the material becomes magnetic. This happens if the energy gained from the electrons lining up is greater than the energy lost.

This idea led to the "Stoner criterion." This is a rule that helps scientists predict if a material will be ferromagnetic (magnetic) or not. If a material meets the Stoner criterion, it means its electrons are likely to line up and create a strong magnetic field.

Awards and Recognition

Edmund Stoner received many honors for his important work.

• In May 1937, he was chosen as a Fellow of the Royal Society. This is a very high honor for scientists in the United Kingdom.
• The E.C. Stoner building at the University of Leeds is named after him. This shows how much his work is valued at the university where he taught for many years.