Road to the Atomic Age

Road to the Atomic Age

The Atomic Age, one of history’s most important events, took centuries to arrive, as events in science and international affairs evolved. The Atomic Theory, a cornerstone of modern science, was proposed by an early Greek thinker named Democritus. He suggested that everything in the universe was made up of particles so tiny that nothing smaller could exist.

French physicist discovered radioactivity in 1896. A little over a hundred years ago, in early 1896, the French physicist, Henri Becquerel, discovered that a mysterious X-ray was produced by uranium. Becquerel’s achievement was itself based on the work of the German scientist, Wilhelm Conafrad Roentgen, who had discovered X-rays only a few months earlier in November 1895.

Albert Einstein, a German-born physicist provided a remarkable new picture of the universe. The German-born physicist Albert Einstein provided a remarkable new picture of the universe. His Special Theory of Relativity, published in 1905, challenged the views of time and space accepted since Newton’s day.

For over two centuries scientists had unquestionably believed that the basic quantities of measurement—mass, length, and time—were absolute and unvarying. Einstein showed that in fact they depended very much on the relative motion between the observer and whatever was being observed.

The Relativity Theory showed that mass could be converted directly into energy, and that a minute piece of mass could release a vast amount of energy.

Einstein’s Letter to FDR
Convinced that it was essential for the Americans to develop an atomic bomb before the Germans did, Einstein wrote to the President.

FDR’s Response
President Roosevelt’s response ultimately led to the Manhattan Project. President Roosevelt replied to Einstein in a letter marked by its subtlety. He stated he was convening a board with representatives from the Bureau of Standards, the Army, and the Navy to investigate Einstein’s suggestions. This set into motion the events which led to the Manhattan Project. CLICK HERE TO VIEW FDR"S RESPONSE LETTER (NEED FROM CLIENT)

The Atomic Theory of Matter
(c.460 BCE - c.370 BCE)
The Atomic Theory, a cornerstone of modern science, was proposed by an early Greek thinker, Democritus.

Atomic Weights
(1808)
John Dalton, an English chemist, stated that each atom of any given element is identical to every other atom of that element, including weight.

The Periodic Table
(1871)
Dmitry Mendeleyev, a Russian chemist, revealed the basic importance of atomic weights and of nuclear structure. His work also showed the significance of structure in comprehending the behavior and properties of matter.

Cathode Rays
(1887)
Sir William Crookes, an English chemist and physicist, pioneered work on cathode rays.

X-Rays
(1895)
While studying cathode rays, German physicist Wilhelm Röentgen noticed some glowing barium platinocyanide across the room from his experiment. This led to the discovery of X-rays. His work helped found a major new medical technique and played an important role in revealing the secrets of the atom and its nucleus.

Radioactivity
(1896)
French physicist Antoine Henri Becquerel discovered radioactivity.

The Electron
(1897)
English physicist Sir J. J. Thomson explained the nature of the electron.

Radium
(1902)
Marie Curie and her husband, Pierre, discovered the radioactive elements polonium and radium. Their work confirmed the existence of radioactivity.

E=mc2
(1905)
For more than two centuries, scientists had unquestionably believed that the basic quantities of measurement—mass, length, and time—were absolute and unvarying. The German-born physicist Albert Einstein showed that in fact they depended very much on the relative motion between the observer and whatever was being observed.

The Nuclear Model
(1909)
Sir Ernest Rutherford’s great contribution to modern science was to show what happens to an element during radioactive decay. This enabled him to construct the first nuclear model of the atom, a cornerstone of present-day physics.

The Electron Orbit
(1913)
Niels Bohr modified Rutherford’s model of the atom to incorporate the ideas of quantum physics. This required a new mechanism for the way electrons emitted energy.

Transformation of Atoms
(1919)
Rutherford’s work, which he published in 1919, demonstrated that atoms could be transformed from those of one element into those of another by means of artificial tampering with the nucleus. Far more important, his experiment demonstrated that the nucleus of an atom could be breached.

The Neutron
(1932)
British physicist Sir James Chadwick is best known for discovering the neutron, one of the fundamental particles making up the nucleus of atoms. The neutron differed from all other particles then known by having no electrical charge.

The Atom is Split
(1932)
Sir John Douglas Cockroft and his colleague, Ernest T. S. Walton, developed the Cockroft-Walton particle accelerator. Using it in 1932, they managed to boost the speed of protons to the point where the voltage was high enough to energize each atom of lithium, their target metal, to form two atoms of helium. This was the first example of man-made nuclear transformation.

Uranium and Fission
(1938)
German scientists Otto Hahn and Fritz Strassmann discovered that a tiny portion of the uranium atom’s mass could be converted into an estimated 200 million electron volts of potentially usable energy. This process was to be called fission.