eehardy's blog

    Certain examples would suggest Aristotle’s idea of gravity originating from elements nature to be true, such as dropping an rock and a leaf at the same time. The rock would fall to the ground faster, since it is heavy like the core of the earth. However, Italian scientist Galileo had suspicions about the veracity of this experiment and decided to test it out himself. He experimented by rolling balls of different masses down sloped planes and found that it was possible to have two balls of different masses reach the bottom of the plane at the same time. This discovery suggested that the rate of acceleration to the earth is universal, a novel concept that contradicted Aristotle’s theory of gravity. 

    Physicist Isaac Newton built off of this idea and made a great leap in the theory, shortly after Galileo’s experimentation. He made a proposition in 1687 that was tremendously successful in predicting the strength of gravity. Isaac believed that the force of gravity that causes a ball thrown into the air to retreat back to the earth was the same force that caused the planets to orbit around the sun. His "Law of Universal Gravitation" states that a particle attracts every other particle in the universe. The degree of this attraction is proportional to the product of their masses and is inversely proportional to the square of the distance between their centers. It is defined by the equation F=(G*m1*m2)/r^2^, where m1 and m2 are the masses of the particles, r is the distance between them, and G is the “gravitational constant."  It took another 250 years before this a new theory suggested the Law of Universal Gravitation to be incorrect, due primarily to the fact that this theory works for most practical purposes. 

Certain examples would suggest Aristotle’s idea of gravity to be true, such as dropping an rock and a leaf at the same time. The rock will fall to the ground faster. However, Italian scientist Galileo had his suspicions about the veracity of this experiment and decided to put it to the test. He experimented by rolling balls of different masses down sloped planes and found that it was possible to have two balls of different masses reach the bottom of the plane at the same time. This discovery suggested that the rate of acceleration to the earth is universal, a novel concept that contradicted Aristotle’s theory of gravity. 

Physicist Isaac Newton built off of this idea, shortly after Galileo, and made a great leap in the theory. He made a proposition in 1687 that had tremendous success in predicting the strength of gravity. Isaac believed that the force of gravity that causes a ball thrown into the air to retreat back to the earth was the same force that caused the planets to orbit around the sun. His Law of Universal Gravitation says that a particle attracts every other particle in the universe. The degree of this attraction is proportional to the product of their masses and is inversely proportional to the square of the distance between their centers.  It took another 250 years before this a new theory showed this one to be incorrect, and this is because for most practical purposes this theory is “correct.” Newtonian gravity, in combination with Newtonian motion, explains the orbit of the planets around the sun, the orbits of the moons around the planets, gravity as we see experience it here on earth, and the ocean tides. Whenever astronomical measurements seemed to be in discordance with Newtonian gravity, it was ultimately found that the measurements were for some reason incorrect. One example is the course of Uranus rotating about the sun. Measurements of it’s orbit appeared to violate Newtonian gravity. However, scientists speculated that some undiscovered planet could possibly be pulling on Uranus and altering it’s orbit and a man named U.J.J. Le Verrier decided to put this theory to the test and calculated where this mysterious planet may be based on Newton’s laws of gravity and motion. When he trained his telescope to aim at that spot, there the planet (Neptune) was, exactly where Newton’s Laws said it should be.

  In the lab, 0.064 g sodium hydroxide and 0.200g 2-naphthol  were added to a flask. 3mL ethanol was then added to the flask. Then the solution was refluxed for 25 minutes and cooled for 3 minutes. 0.2mL N-butyl iodide was added to the solution and the solution was refluxed for one hour. Around the 10 minute left point in the reflux, 25 mL water was cooled in an ice bath. The reaction mixture was poured over 10 g of ice in a beaker and stirred until 95% of the ice had melted. The product was then collected via suction filtration. The product was rinsed with ice-cold water and dried under suction for 25 minutes. The melting point of the product was then taken. To analyze the polarity of the product, thin layer chromatography (TLC) was performed. A small amount of product was dissolved in ethyl acetate and a small amount of 2-naphthol was also dissolved in ethyl acetate. Then three TLC plates were prepared with three spots A, B and C from left to right (A was the 2-naphthol solution, B was 50% 2-naphthol solution and 50% product solution, and C was the product solution). One plate was run in 75:25 hexanes:EtOAc solution; one plate was run in 25:75 hexanes:EtOAc solution; and the third plate was run in 60:40 hexanes:EtOAc solution.

The cycohexanol was reacted using heat and a strong acid and the alkene was obtained in 57% yield. The distillate range was 68°C-70°C, suggesting that the compound was relatively impure since the range was lower than expected. When either bromine or KMnO4 were added to the cyclohexene product it did not mix so it remained clear, but in the cyclohexane product they did mix and turned a reddish brown color in the case of the bromine and a purplish color in the case of the KMnO4, which were the expected results. The Gas chromatography suggested that the mixture was around 76% cyclohexene, which suggested that the actual yield was about 0.014 mol, hence the theoretical yield of 57%. The resulting substance was relatively impure.

You certainly do not have to be a physicist to know of gravity. Gravity is not some obscure concept mentioned only in the lingo of die-hard astronomy fans, like a “quasar" or a "red giant." Gravity is a concept known by toddlers and astrophysicists alike. From a young age, we learn that when we throw a ball up, it must come back down. We learn that if we slip on the monkey bars, gravity will bring us hurtling toward the ground. And sadly, we learn that we cannot fly. These lessons are all thanks to gravity.  But while anyone and everyone recognizes that gravity exists, it is likely that far fewer people have pondered where gravity comes from. Few have likely asked themselves, “what really IS gravity?" That is where physicists come into play, and the answer is not quite as simple as the concept itself. 

One of the most prominent great thinkers of Ancient Greece, philosopher Aristotle, took a stab at theorizing the nature of gravity in the 4th century B.C. Aristotle believed that different elements gravitated toward different sources based on their own internal nature, rather than an external compelling force. The consensus at that time was that the earth was the center of the universe, supported by the complex diagrams constructed by the Roman Ptolemy which could be used to predict the motion of the visible planets. Thus, Aristotle believed that heavy elements were trying to seek their "correct" place at the center of the universe (the center of the earth).  For this reason rocks would fall to the ground, but lighter elements like steam would rise to their own natural and "correct" place in the sky. This led Aristotle to the conclusion that heavier elements fall faster.

You certainly do not have to be a physicist to know of gravity. Gravity is not some obscure concept mentioned only in the lingo of die-hard astronomy fans, like a quasar or a red giant. Gravity is a concept known by toddlers and astrophysicists alike. From a young age, we learn that when we throw a ball up, it must come back down. We learn that if we slip on the money bars, gravity will bring us hurtling toward the ground. And sadly, we learn that we cannot fly. These lessons are all thanks to gravity. And it doesn’t stop there. We all feel gravity constantly, pulling us to the ground when we are sitting, standing, running, skipping, and jumping. John Mayer even wrote a song about it. We all know of gravity’s existence just like we all know the sky is blue. But while anyone and everyone can recognize that gravity exists, not many people have probably sat down and really asked themselves, from what source does gravity originate? What really IS gravity? And that is where physicists come into play, and the answer is not quite as simple as the concept itself. 

Another famous experiment that supports General Relativity is the deflection of light by the sun. Previous theories of gravity held that light would not be affected by gravity since it has no mass. However, Einstein thought otherwise. His Equivalence Principle predicts that light will curve in the presence of a gravitational field. The principle states that the effects of a gravitational field are the same as the effects of those in an accelerated frame of reference. Gravity would cause a person in a gravitational field to accelerate with g, the acceleration due to gravity. However, if the person’s frame of reference were to be accelerated at g when they were not in a gravitational field, all of the effects on them would be “equivalent” to how they would be in a gravitational field. Thus, in essence, a gravitational field can be created. Now, if a person was in the accelerating frame of reference and was to shine a beam of light out into an inertial reference frame of space, it would appear as though the light is curving downward since the particles of light emitted earlier would be lower than those emitted as the acceleration proceeds higher. And since this accelerated reference frame is equivalent to a gravitational field, the same thing would apparently happen in a gravitational field; light would curve. But according to classical physics, the force due to gravity is mass times acceleration… so how would light be affected since it has zero mass? And the curvature of spacetime explains this problem perfectly since light doesn’t need mass to follow the curve of spacetime. Thus, according to Einstein, light is deflected by gravity.

Another famous experiment that supports General Relativity is deflection of light by the sun. Previous theories of gravity held that light would not be affected by gravity since it has no mass. However, Einstein showed this idea to be incorrect. Taking a look at Einstein’s Equivalence Principle which relates to gravity, we can imagine this idea. Einstein’s equivalence principle states that the effects of a gravitational field are the same as the effects of those in an accelerated frame of reference. Gravity would cause a person in a gravitational field to accelerate with g, the acceleration due to gravity. However if the person’s frame of reference were to be accelerated at g when they were not in a gravitational field, all of the effects on them would be “equivalent” to how they would be in a gravitational field. Thus, in essence, a gravitational field can be created. Now if a person were in the accelerating frame of reference and were to shine a beam of light out into an inertial reference frame of space, it would appear that the light is curving downward, since the particles of light emitted earlier will be lower than those emitted as the acceleration proceeds higher. And since this accelerated reference frame is equivalent to a gravitational field, the same thing would apparently happen in a gravitational field; light would curve. But according to classical physics, the force due to gravity is mass times acceleration… so how would light be affected since it has zero mass? And the curvature of spacetime explains this problem perfectly, since light doesn’t need mass to follow the curve of spacetime. Thus, according to Einstein, light is deflected by gravity.

(1).Another study described spider webs as depending upon the mechanical performance of capture threads, and states that web function arises from the architecture and mechanical performance of silk (3.) This study also used microscopy, and measured the web thickness of different web types: orb webs, funnel webs, dome webs, and irregular mesh webs. The different types of webs yielded different thicknesses on average, with orb webs being the thickest. Since spider webs must be strong enough to withstand the weight of the spider on the web, and be durable enough to support the spider’s movement, it is plausible that spider weight could also be a factor in web thickness, in addition to web type.