Léon Foucault pendulum suspended from the roof of the Panthéon, Paris. The experiment caused a sensation in both the learned and popular worlds, and ""Foucault pendulums"" were suspended in major cities across Europe and America and attracted crowds. In the following year he used (and named) the gyroscope as a conceptually simpler experimental proof. In 1855, he received the Copley Medal of the Royal Society for his 'very remarkable experimental researches'. Earlier in the same year he was made "physicien" (physicist) at the imperial observatory at Paris. In September 1855 he discovered that the force required for the rotation of a copper
History of physics paper on the conservation of energy but his lack of academic training led to its rejection. In 1842, Christian Doppler proposed the Doppler effect. In 1847, Hermann von Helmholtz formally stated the law of conservation of energy. In 1851, Léon Foucault showed the Earth's rotation with a huge pendulum (Foucault pendulum). There were important advances in continuum mechanics in the first half of the century, namely formulation of laws of elasticity for solids and discovery of Navier–Stokes equations for fluids. In the 19th century, the connection between heat and mechanical energy was established quantitatively by Julius Robert von Mayer and