100 Greatest Discovery Video Notes Summary

The first discovery in chemistry, the discovery of oxygen by Joseph Priestley in the 1770s, started when scientists searched for “new air”” known as gas. Later, Antoine Lavoisier named it oxygen and described its role. The next discovery was the atomic theory by John Dalton, who at first called the atomic weights “the relative weights of ultimate particles”. His atomic theory was the revolutionary system that described the relationship between atoms and elements. Atoms combining into molecules was another discovery found when Gay Lussac saw that the gases produced twice the volume when combining equal volume of different gases. In 1811, Amedeo Avogadro realized that the assumptions that gases remain of single atoms to be wrong and that gases actually remain of multiple atoms, molecules. The next discovery was the synthesis of urea in the 19th century when Friedrich Woehler synthesized urea from inorganic materials, proving that substances made by living things can be reproduced with nonliving substances. The periodic table of elements is next discovery and is discovered by Dmitry Mendeleyev, who made cards and wrote the name of elements, atomic weight, typical properties and its similarities with other elements, and after arranging them around, he saw that they fall into seven vertical groupings.

Humphry Davy discovered and proved the power of electricity to react with chemicals and transform, which later lead to rise in aluminum industry, solar panels, semi conductors and etc. Later, electrons where discovered by J.J Thomson and became known to be smaller than other atoms. John Hyatt discovered a way to exploit the long stringing molecules of cellulous and created the first plastic. About fifty years later, Leo Baekeland took the next step and with two chemicals from coal he discovered the first fully synthetic plastic. The next discovery was the idea that electrons form chemical bonds. Early in 1900’s, Gilbert Lewis explained that electrons and atoms went in shells around the nucleus and theorized that two chemical elements might combine to form a compound when they give up or accept electrons from their outer shells (ex: table salt). In1850, Gustav Kirchhoff and Robert Bunsen found that atoms have signatures of light. They conducted series of experiments to know why substances emitted specific colors when placed in fire and resulted with the idea that color determines what elements are present in substance. They also built the first stethoscope to help them see the spectra coming from heated substances.