<h2>Gravity</h2>
<p>The theory of gravity has been slowly developing since the beginning of the 16th century. Galileo Galilei is credited with some of the earliest work. At the time it was widely believed that heavier objects accelerated faster toward the earth than light objects did. Galileo had a hypothesis that this was not true, and performed experiments to prove this.</p>
<div class="wp-caption alignnone" id="attachment_93056" style="width: 363px"><a href="https://data.ulearngo.com/assets/432d86b7-741f-4647-b1ac-0f196dd04411"><img alt="isaac-newton" class="size-full wp-image-93056" height="500" src="https://data.ulearngo.com/assets/432d86b7-741f-4647-b1ac-0f196dd04411" width="363"/></a><p class="wp-caption-text">Portrait of Isaac Newton (1642-1727). Image credit: http://www.newton.cam.ac.uk/art/portrait.html</p></div>
<p>Galileo's work allowed Sir Isaac Newton to hypothesise not only a theory of gravity on earth, but that gravity is what held the planets in their orbits. Newton's theory was used by John Couch Adams and Urbain Le Verrier to predict the planet Neptune in the solar system and this prediction was proved experimentally when Neptune was discovered by Johann Gottfried Galle.</p>
<p>Although a large majority of gravitational motion could be explained by Newton's theory of gravity, there were things that did not fit. But although a newer theory that better fit the facts was eventually proved by Albert Einstein, Newton's gravitational theory is still successfully used in many applications where the masses, speeds and energies are not too large.</p>
<h2>Thermodynamics</h2>
<p>The principles of the three rules of thermodynamics describe how energy works, on all size levels (from the workings of the Earth's core, to a car engine). The basis for these three rules started as far back as 1650 with Otto von Guericke. He had a hypothesis that a vacuum pump could be made, and proved this by making one. In 1656 Robert Boyle and Robert Hooke used this information and built an air pump.</p>
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<h3>Fact:</h3>
<p>Robert Boyle should be a familiar name to you. Boyle's law came about from his air pump experiments, where he discovered that pressure is inversely proportional to volume at a constant temperature (p \(\propto \frac{1}{\text{V}}\) at constant T).</p>
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<p>Over the next \(\text{150}\) years the theory was expanded on and improved. Denis Papin built a steam pressuriser and release valve, and designed a piston cylinder and engine, which Thomas Savery and Thomas Newcomen built. These engines inspired the study of heat capacity and latent heat. Joseph Black and James Watt increased the steam engine efficiency and it was their work that Sadi Carnot (considered the father of thermodynamics) studied before publishing a discourse on heat, power, energy and engine efficiency in 1824.</p>
<p>This work by Carnot was the beginning of modern thermodynamics as a science, with the first thermodynamics textbook written in 1859, and the first and second laws of thermodynamics being determined in the 1850s. Scientists such as Lord Kelvin, Max Planck, J. Willard Gibbs (all names you should recognise) among many many others studied thermodynamics. Over the course of 350 years thermodynamics has developed from the building of a vacuum pump, to some of the most important fundamental laws of energy.</p>
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Gravity and Thermodynamics

Physics is a science discipline concerned with the nature and properties of matter and energy. Physics topics include mechanics, heat, light and radiation, sound, electricity, magnetism, the structure of atoms, and so on.

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Gravity and Thermodynamics

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