This title explains the discovery of elements and the Law of Conservation of Mass, using experiments to illustrate or demonstrate these concepts. It shows how discoveries about air pressure increased suspicion that atoms exist. It shows the path to the mathematical conclusion that atoms exist, based on weight ratios of compounds, and shows us how to perform chemical equations.

Streaming video file encoded with permission for digital streaming by Infobase on January 28, 2015. Link to website with Teacher's notes and Question Sheet for students available under Additional info tag.

Elements --(1:10) -- Combining and Breaking Apart -- (3:02) -- Iron Production -- (1:14) -- Lavoisier's List of Elements -- (2:10) -- What Is Fire? -- (0:54) -- Law of Conservation of Mass -- (2:27) -- Example of Conservation of Mass -- (1:22) -- Physical Evidence of Atoms -- (3:15) -- Bernoulli -- (1:02) -- Atoms Discovered -- (3:46) -- Dalton Demonstrates Atoms -- (2:07) -- Organizing Knowledge -- (2:16) -- Summary: The Discovery of Atoms -- (0:38) -- Credits: Shedding Light on Atoms Episode 3: The Discovery of Atoms -- (0:13). Part A: Introduction: a brief recap on atoms, elements and compounds Part B: Copper and Copper Oxide: We demonstrate how copper can combine with oxygen to produce copper oxide and how copper oxide can be broken back down into copper and oxygen. We explain how blast furnaces produce metals like iron from iron ore. Part C: Lavoisier’s List of Elements: The first (fairly accurate) list of elements was published by Lavoisier in 1789. The Ancient Greek 4-element theory was laid to rest. We explain what fire is. Part D: The Law of Conservation of Mass: Among other achievements, Lavoisier proposed the Law of Conservation of Mass. In any chemical reaction, the mass of the reactants equals the mass of the products. Numerous chemical reactions are shown to demonstrate. Part E: Some Physical Evidence: In the 1700s, experiments involving air pressure suggested that air was made of tiny, rapidly moving particles. We demonstrate and explain what air pressure is and why it occurs. However, though air pressure alone could not prove that atoms existed, it did lead many towards a belief in atoms. Part F: Atoms are Discovered: When compounds were analysed carefully, it was realized that they always show a fixed ratio of the weights of the elements that make them up. John Dalton used this data to propose the existence of atoms. Later, Jons Berzelius came up with our “modern” system of chemical notation.