Chemistry is the science of matter and chemicals. It involves the study of elementary particles, atoms, molecules, substances, metals and other aggregates of matter in solid, liquid, and gas states, as well as their interactions, reactions and transformations. These interactions are usually the result of interactions between atoms and the chemical bonds that hold atoms together. Common laboratory equipment used in chemistry include test tubes, beakers, Bunsen burners, flasks, and tools for measuring, stirring, and filtering substances. Some influential historical figures in the development of chemistry include Dmitri Mendeleyev, Antoine Lavoisier, Henry Cavendish, Amedeo Avogadro, Jons Jakob Berzelius, John Dalton