Ernest Rutherford

“Father of Nuclear Physics”

Nobel Prize in Chemistry (1908)

Element 104, Rutherfordium, is named in his honor

Notable Awards:

• Text

Known for:Father of nuclear physics

Rutherford modelRutherford scattering

Rutherford backscattering spectroscopy

Discovery of protonRutherford (unit)

Coining the term 'artificial disintegration'

Early Life and Education:• Ernest Rutherford was born on August 30, 1871, Spring Grove

near Nelson, New Zealand• Ernest studied in a Government school and after he completed

his schooling he won a scholarship to Nelson Collegiate School.

• At Cambridge, he worked as a research student at the Cavendish Laboratory under Professor J.J Thomson.

• Later he left for Canada when he was given the opportunity to take the chair of physics at McGill University in Montreal.

• In 1900 Rutherford married Mary Newton, only daughter of his landlady in Christchurch.

Contribution to the Field of Physics

• 1896 Rutherford and Thomson were working together on the conductivity of electricity in gases using x rays

• While experimenting on radioactivity during 1899, Rutherford discovered two distinctive types of radiation emitted by thorium and uranium which he named alpha and beta. These rays were distinguished on the basis of penetrating power.

These could be distinguished by their ability to penetrate materials: α rays would not pass through a thin piece of paper; β radiation was more powerful and could penetrate thin sheets of metal foil.

Radiation was caused by atoms of

radioactive material breaking apart.

(a) In her thesis, Marie Curie reported the drawing on the left which showed the effect of a magnetic field on the three forms of radioactivity.   Alpha-particles were deflected more slowly than beta-particles, which suggested that alpha-

particles were heavier than beta-particles.  Gamma-rays were not affected by a magnetic field.  (b) The effect of an electric field on the different forms of

radioactivity shows that alpha-particles and beta-particles are both electrically charged, but they carry charges with opposite signs.  Gamma-rays are not

affected by an electric field and therefore have no electric charge

Gold

Summary:Rutherford discovered and named alpha and beta

decay and coined the terms alpha, beta, and gamma rays. He demonstrated radioactivity was the spontaneous disintegration of atoms and was

the first person to artificially disintegrate an element. He identifed alpha particles as helium nuclei. Rutherford's gold foil experiment helped describe the nuclear structure of the atom. The

deflection of the alpha particles implied the existence of a dense, positively charged central region containing most of the atomic mass. In 1920, he hypothesized the existence of the

neutron.