 # Philosophiae Naturalis Principi Newton's Three Laws Of Motion

explanatory Essay
992 words
992 words In 1687, Newton published Philosophiae Naturalis Principia Mathematica (also known as Principia). The Principia was the “climax of Newton's professional life” (“Sir Isaac Newton”, 370). This book contains not only information on gravity, but Newton’s Three Laws of Motion. The First Law states that an object in constant motion will remain in motion unless an outside force is applied. The Second Law states that an object accelerates when a force is applied to a mass and greater force is needed to accelerate an object with a larger mass. The Third Law states that for every action there is an opposite and equal reaction. These laws were fundamental in explaining the elliptical orbits of planets, moons, and comets. They were also used to calculate …show more content…

#### In this essay, the author

• Explains newton's three laws of motion, which were fundamental in explaining the elliptical orbits of planets, moons and comets.
• Explains that newton began to show interest in light while away from trinity college. the experiment led to the formation of the modern theory of light quanta.
• Explains that isaac newton created an intricate experiment to test and verify the current theory of light. the key to his experiment was a glass prism.
• Explains newton's experimentum crucis, where he placed a second prism 5 or 6 yards away from the first, and rotated them to test if this would have an effect on the light.

His problem statement (a description of the issue being tested during the experiment) was: Can Hooke’s theory of light and the currently accepted theory be verified? The key to Newton’s experiment was a glass prism. According to the book, Isaac Newton (written by Gale E. Christianson), glass prisms were believed to have displayed the phenomena of the scale of light and give proof that the scale of light went from a bright red (color closest to white) to a dull blue (color closest to black). It was also believed that all of these colors were modifications of true white. To test this theory, Newton bought a glass prism “to try therewith the celebrated phenomena of colors” (More, 389). Newton took his prism to his upstairs bedroom and made sure that the room was completely darkened. He then positioned the prism on a table and drilled a one-eighth inch hole into the window shutter so that the light would pass through the prism at a specific angle and was projected onto a wall ("Newton and the Colour of Light"). According to the accepted theory of light, should light pass through a glass prism at that angle, the colors of the spectrum of light should be projected in a perfect circle. However, Newton observed that the colors were arranged into a rectangular shape and the pattern was wider than was predicted. Newton concluded that each color refracted at a different angle as it passed …show more content…

In this experiment, Newton placed a second prism 5 or 6 yards away from the first. At first, when the light passed through the prisms, his results were the same as the first experiment. However, when the prisms were moved farther away from the wall onto which the light was being projected, the light projected from the prisms became white again. When they were moved even farther, the light became colored again, but the color scale was inverted from the original scale. According to the accepted theory of light, the second prism changed the color of the light projected onto the wall. Therefore, Newton’s results once again contradicted the accepted theory of light. He also rotated the prisms to test if this would have an effect on the light, but it did not. Due to these observations, Newton concluded that light was in fact a combination of all light on the spectrum of light, not just a mixture of light and