At the beginning of the eighteenth century, a vital question arose in the scientific community that sparked discussions among scientists and the question was “what is light made of? ". Sir Isaac Newton, one of the greatest scientists and mathematicians of all time, proposed that light was made up of tiny particles called corpuscles. But around the same time, Newton's corpuscular theory of light was challenged by Christian Huygens. According to Huygens, light was made up of waves and not particles (Spring and Davidson). Even though both theories have some differences, they are both true; light is composed of both particles and waves. The theories of Newton and Huygens triggered a great debate on the structure of light. Both studied light in depth and developed their theories. Newton's corpuscular theory considers the prism experiment which concluded that light travels as a stream of particles that proceed in a straight line until they are refracted or deflected by a solid surface (Spring and Davidson). In contrast, Huygens' wave theory is based on the fact that light does not travel in a straight line but rather travels in a wave pattern. Huygens demonstrated that the edges of shadows are not perfectly sharp and concluded that light must be a wave and diffracts when it passes through an opening (Hernandez). These were the first arguments provided by Newton and Huygens to validate their theories. But this was not enough for the scientific community to consider one correct compared to the other. Both theories required further testing. Another important difference was found in their explanation of light reflecting from a smooth surface, such as a mirror. According to Newton's particle theory, when light, like... in the center of the paper... claimed the discovery of the answer. Thanks to the contribution of great scientists such as Max Planck, Albert Einstein and many others, the scientific community today supports the theory of Wave-Particle duality, according to which every particle has a wave-type nature (Spring and Davidson). Even though both theories have some differences, they are both true; light is composed of both particles and waves. Although these theories sparked a centuries-long debate, Quantum Mechanics was born as a result of research conducted to demonstrate the credibility of the theories (Spring and Davidson). Works Cited Hernandez, Maryann. "Wave-particle duality". Chemwiki. University of California, n.d. Web. 07 December 2013. Primavera, Kenneth R. and Michael W. Davidson. "Light: particle or wave?" Molecular expressions. Florida State University, 1 August 2003. Web. 06 December. 2013.