1 Isaac Newton : Isaac Newton is one of the most famous scientists of all time, and considered by many to be the greatest scientists to ever live. He contributed massively to the fields of maths, optics, and mechanics. Newton is the man who discovered gravity, after he witnessed an apple falling from a tree. He then went on to explain it’s principles by inventing calculus, since nothing else could. He also described the three laws of motion which laid the groundwork for for classical mechanics. Newton also built the first practical reflecting telescope, and developed a theory of colour based on his observation that a prism decomposes white light into the many colours of the visible spectrum.