Ernest Marsden was a prominent physicist born in New Zealand in 1889. He is famous for his contribution to the atomic theory, which was a significant turning point in the field of physics. His work with Ernest Rutherford, his mentor and collaborator, led to several discoveries that changed the way we understand the atom.

The Early Years

Marsden began his academic career at Victoria University College in Wellington, New Zealand. He studied mathematics and physics and graduated with honors in 1909. After completing his studies, he worked as a science teacher for some time before joining the research team at the University of Manchester.

The Discovery of Atomic Nucleus

At Manchester, Marsden worked under Ernest Rutherford’s guidance on several experiments related to radioactivity. In 1909, they conducted an experiment where they shot alpha particles at a thin sheet of gold foil. They expected the alpha particles to pass through the foil without any deflection as per their understanding of the atomic theory at that time.

However, they found that some alpha particles deflected from their path while passing through the gold foil. This observation contradicted their previous understanding of atoms being made up of positively charged protons and electrons distributed uniformly throughout its volume.

Contributions to Atomic Theory

This experiment led to further experiments by Rutherford and Marsden which resulted in the discovery of atomic nucleus: a tiny region at the center of an atom where most of its mass is concentrated and positively charged protons are located. This discovery revolutionized atomic theory and set a new direction for future research on subatomic particles.

Marsden also contributed significantly to our understanding of X-rays by studying how they interact with matter and developing techniques for their practical use.


In conclusion, Ernest Marsden’s contribution to atomic theory was significant, and his work with Ernest Rutherford on the discovery of atomic nucleus changed the way we perceive the atom. His research also helped to develop new techniques for studying subatomic particles and paved the way for further discoveries in the field of physics.