John Frank Allen Canadian and British experimental physicist Date of Birth: 06.05.1908 Country: Canada

1. Early Life and Education
2. Research Career in Canada
3. Collaborative Research in England
4. Professorship and Scientific Discoveries
5. Superfluidity of Helium
6. Thermal Conductivity Anomaly
7. Fountain Effect
8. Recognition and Legacy

Early Life and Education

John Frank Allen, a distinguished Canadian and British experimental physicist, was born in Winnipeg, Manitoba, Canada. His academic journey began at the University of Manitoba, where he graduated in 1928. Two years later, he earned a degree from the University of Toronto.

Research Career in Canada

After completing his studies, Allen worked at the National Research Council in Ottawa from 1930 to 1933. His research focused on low-temperature physics, particularly the properties of liquid helium.

Collaborative Research in England

In 1934, Allen relocated to England and secured a lectureship at the University of Cambridge. Simultaneously, he collaborated at the Mond Laboratory from 1935 to 1944, where he made significant contributions to the field.

Professorship and Scientific Discoveries

In 1947, Allen was appointed Professor at the University of St. Andrews in Scotland, a position he held until 1978. His research expanded to include superconductivity.

Superfluidity of Helium

In 1938, Allen, along with A. Misener, conducted groundbreaking experiments that led to the discovery of superfluidity. This phenomenon, observed in liquid helium II, exhibited extremely low viscosity when flowing through narrow capillaries and slits.

Thermal Conductivity Anomaly

Allen also investigated the thermal conductivity of liquid helium and confirmed the anomalous findings of W. Keesom. Notably, he found that the heat flow was not proportional to the temperature difference. As the temperature decreased, thermal conductivity increased drastically, far exceeding that of helium I.

Fountain Effect

In collaboration with H. Jones, Allen discovered the fountain effect in liquid helium in 1938. This effect, later termed the thermomechanical effect, involves the creation of a fountain of liquid helium when heat is applied.

Recognition and Legacy

Allen's contributions to low-temperature physics were widely acknowledged. He became a Fellow of the Royal Society of London in 1949 and the Royal Society of Edinburgh. His work continues to shape the field and inspire future generations of researchers.