A Journey Through Atomic Theory

John Dalton

Dalton proposed a new atomic theory that became the foundation of modern chemistry. He envisioned atoms as tiny, indestructible spheres. Explore his key ideas below.

Michael Faraday

Faraday's experiments with electrolysis showed that passing electricity through water could decompose it into hydrogen and oxygen. This suggested a fundamental link between electricity and matter.

Interactive Electrolysis

Faraday passed a current through water. Click "Apply Voltage" to see what he observed.

Radioactivity

Becquerel and the Curies discovered that atoms weren't indestructible. Certain elements, like Uranium, spontaneously decay, releasing energy and particles. This shattered Dalton's model.

The Accidental Discovery

Becquerel left uranium salts on a photographic plate in a dark drawer. Click to see what he found.

J.J. Thomson

Thomson's experiments with cathode ray tubes led to a revolutionary discovery: the atom was not indivisible! He had found the first subatomic particle: the electron.

Interactive Cathode Ray Tube

The Plum Pudding Model

Based on his discovery, Thomson proposed the "plum pudding" model, where negative electrons were embedded within a sphere of positive charge.

Ernest Rutherford

Rutherford fired alpha particles at a thin sheet of gold foil. He expected them to pass through, but some were deflected! This led to the discovery of the atomic nucleus.

The Gold Foil Experiment

Click the button to see what Rutherford's team observed.

The Nuclear Model

Rutherford concluded the atom is mostly empty space, with a tiny, dense, positively-charged nucleus at the center, overturning the Plum Pudding model.

The Story Continues...

Rutherford's nucleus opened the door to the strange and wonderful world of quantum mechanics. The next chapter in atomic theory would be even more revolutionary.

Next: Explore the Quantum Atom →