Pressure Definition, Units, and Examples

In science, pressure is a measurement of the force per unit area.  The SI unit of pressure is the pascal (Pa), which is equivalent to N/m2  (newtons per meter squared). Basic Example If you had 1 newton (1 N) of force distributed over 1 square meter (1 m2), then the result is 1 N/1 m2 1 N/m2 1 Pa. This assumes that the force is directed perpendicularly toward the surface area. If you increased the amount of force but applied it over the same area, then the pressure would increase proportionally. A 5 N force distributed over the same 1 square meter area would be 5 Pa. However, if you also expanded the force, then you would find that the pressure increases in an inverse proportion to the area increase. If you had 5 N of force distributed over 2 square meters, you would get 5 N/2 m2 2.5 N/m2 2.5 Pa. Pressure Units A bar is another metric unit of pressure, though it is not the SI unit. It is defined as 10,000 Pa. It was created in 1909 by British meteorologist William Napier Shaw. Atmospheric pressure, often noted as pa, is the pressure of the Earths atmosphere. When you are standing outside in the air, the atmospheric pressure is the average force of all of the air above and around you pushing in on your body. The average value for the atmospheric pressure at sea level is defined as 1 atmosphere, or 1 atm. Given that this is an average of a physical quantity, the magnitude may change over time based on more precise measurement methods or possibly due to actual changes in the environment that could have a global impact on the average pressure of the atmosphere. 1 Pa 1 N/m21 bar 10,000 Pa1 atm ≈ 1.013 Ãâ€" 105 Pa 1.013 bar 1013 millibar How Pressure Works The general concept of force is often treated as if it acts on an object in an idealized way. (This is actually common for most things in science, and particularly physics, as we create idealized models to highlight the phenomena we way to pay specific attention to and ignore as many other phenomena as we reasonably can.) In this idealized approach, if we say a force is acting on an object, we draw an arrow indicating the direction of the force, and act as if the force is all taking place at that point. In reality, though, things are never quite that simple. If you push on a lever with your hand, the force is actually distributed across your hand and is pushing against the lever distributed across that area of the lever. To make things even more complicated in this situation, the force is almost certainly not distributed evenly. This is where pressure comes into play. Physicists apply the concept of pressure to recognize that a force is distributed over a surface area. Though we can talk about pressure in a variety of contexts, one of the earliest forms in which the concept came into discussion within science was in considering and analyzing gases. Well before the science of thermodynamics was formalized in the 1800s, it was recognized that gases, when heated, applied a force or pressure onto the object that contained them. Heated gas was used for levitation of hot air balloons starting in Europe in the 1700s, and the Chinese and other civilizations had made similar discoveries well before that. The 1800s also saw the advent of the steam engine (as depicted in the associated image), which uses the pressure built up within a boiler to generate mechanical motion, such as that needed to move a riverboat, train, or factory loom. This pressure received its physical explanation with the kinetic theory of gases, in which scientists realized that if a gas contained a wide variety of particles (molecules), then the pressure detected could be represented physically by the average motion of those particles. This approach explains why pressure is closely related to the concepts of heat and temperature, which are also defined as motion of particles using the kinetic theory. One particular case of interest in thermodynamics is an isobaric process, which is a thermodynamic reaction where the pressure remains constant. Edited by Anne Marie Helmenstine, Ph.D.

Themes Of Good Country People - 769 Words

Flannery O’Connor’s short story â€Å"Good Country People† depicts Hulga, a highly educated woman and has a PhD, is being jerked around by an immoral bible salesman. â€Å"A good man is hard to find† is a story of a grandmother and her family murdered by a horrible man who called â€Å"the misfit† during the road trip. Although â€Å"Good country people† and â€Å"a good man is hard to find† are written by the same author, many elements in those two stories cause them have similar themes in religion, misplace trust and protagonist and antagonist. In â€Å"Good country people†, Hulga believes in nothing and she is one of the non-religious people. Mrs. Hopewell introduces Hulga to the bible salesman that Hulga is an atheist and won’t let Mrs. Hopewell keeps the Bible†¦show more content†¦at last Hulga realizes that a good country people is hard to find in the word. Similarly, the grandmother, one of the central character in â€Å"a good man is hard to find†, believes the misfit’s conscience did not quite gone out of him. Although the grandmother tells the misfit that he is good and won’t kill woman couple of times and she tries to persuade the misfit not to kill her, the grandmother and her family murdered by the inhumane and deadly man in the end of the story. there is doubt that trust is one of the most important element to affect this story. Hulga is an unlikely character in â€Å"good country people† as the protagonist. The actions and beliefs of the protagonist drives the climax of this short story. In the story, hulga changes her name from Joy to Hulga which means hulk and ugly; Mrs. Hopewell said this is the ugliest name she ever heard before. Because of hulga’s PhD in philosophy, she places her faith in wisdom rather than religion. Simply put, Hulga is an unpopular person and the obviously protagonist in the story. The antagonist in the short story â€Å"a good man is hard to find†, the grandmother appears in the short story very first seems like a good but actually she is bad because of her dishonesty and selfishness. In the begging of the story, the grandmother debates with her family where should they go for the road trip because the grandmother â€Å"wanted to visit some of herShow MoreRelatedTheme Of Good Country People1126 Words   |  5 Pagesessay is to correlate the theme of three different stories that had been read. I decided to choose the stories â€Å"Good Country People†, â€Å"Hills Like White Elephants†, and â€Å"The Storm.† I believe that the theme across these stories is to beware of the wolf in sheep clothing. In these stories, there was an antagonist that posed as a protagonist who even though their intentions may have looked well skin deep, the underlying intentions against the main character were not of good intent. I will describe certainRea d MoreMain Themes In Good Country People970 Words   |  4 Pagesshort story â€Å"Good Country People† depicts Hulga, a highly educated woman and has a PhD, is being jerked around by an immoral bible salesman. â€Å"A good man is hard to find†, also written by O’Connor, is a short story of a grandmother and her family murdered by a horrible man who called â€Å"the misfit† during the road trip to Florida. Although â€Å"Good country people† and â€Å"a good man is hard to find† are written by the same author, many elements in those two stories cause them have similar themes in religionRead More Good Country People by Flannery OConnor Characterization as Theme914 Words   |  4 PagesGood Country People by Flannery OConnor Characterization as Theme The Depth of Hulga?s Despair Characterization is the most prevalent component used for the development of themes in Flannery O?Connor?s satirical short story ?Good Country People.? O?Connor artistically cultivates character development throughout her story as a means of creating multi-level themes that culminate in allegory. Although the themes are independent of each other, the characters are not; the development of oneRead MoreTheme Of Redemption And Good Country People By Flannery O Connor s `` A Good Man Is Hard1837 Words   |  8 PagesFlannery O Connor s stories â€Å"A Good Man Is Hard to Find†, and â€Å"Good Country People† both present very similar themes. Within these stories is the theme of redemption, and the way relationships affect the way people interact with each other seem to be a core issue she struggles with. Both stories have a protagonist that have to deal with some type of villain who has little to no belief, while their presence of faith that there is good in people g ets them into the horrible situations that they findRead MoreGeography And The Geography Of Greece1604 Words   |  7 Pagesabout the geography of Greece, all five themes of geography need to be addressed. The five themes of geography are location, place, region, movement, and human-environmental interaction. The absolute location of a specific place is the coordinates of a map using longitude and latitude. A place is an area that is defined by its physical and cultural characteristics. A region is areas that are similar and have definite characteristics. The movement is the way people, products, and ideas travel from oneRead MoreIrony in Good Country People748 Words   |  3 PagesIrony in â€Å"Good Country People† Flannery O’Connor uses characterization, and the themes of good versus evil and the psychological and physical problems of the characters, to create irony in the story. The characterization of both Mrs. Hopewell and Joy/Hulga creates irony, which begins with their names. Then the theme of good versus evil, demonstrated by the belief that country people are â€Å"good†, also creates irony. The story is about a farm owner, Mrs. Hopewell, her onlyRead MoreO Connor s Life1323 Words   |  6 Pagesnature of the Bible Belt, all while characterizing her youthfulness are highlighted in two of her greatest short stories titled; â€Å"Good Country People† (O Connor) and â€Å"A Good Man is Hard to Find† (O Connor). Through the use of Flannery O’Connor’s life and relationship experience, both â€Å"Good Country People† (O Connor) and â€Å"A Good Man is Hard to Find† (O Connor) depicts themes of resentment surrounding religion, old south traditions, and the drive to find acceptance in a rough community. AdvertisementRead MoreFlannery O’connor’s Use of Symbolism, Theme, and Religion1057 Words   |  5 PagesFlannery O’Connor’s Use of Symbolism, Theme, and Religion In this essay I will be covering the similarities, differences, and uniqueness of theme in three of Flannery O’Connor’s short stories. The stories I will be discussing are A Good Man is Hard to Find, Revelation, and Good Country People. O’Connor was considered to be a type of religious propaganda. At least one character in her stories had a name or behavior that reflected religion. Her stories most often had an aggressive twist to them.Read MoreGood vs. Evil Found in Beowulf807 Words   |  3 PagesGood vs. Evil Found in Beowulf In the story of Beowulf, there are many different themes found. Many people argue the main theme found in this story. This has been argued for a very long time and will go on for many more years to come. Although many themes in this story stick out and a main theme will never be accepted, one main theme is very noticeable in the story of Beowulf. The main theme found in Beowulf is good versus evil. Good versus evil is very easy to recognize. â€Å"Some peopleRead More Comparing Pride in A Good Man is Hard to Find, Good Country People and Revelation989 Words   |  4 PagesPride in A Good Man is Hard to Find, Good Country People and Revelation    Pride is a very relevant issue in almost everyones lives. Only when a person is forced to face his pride can he begin to overcome it. Through the similar themes of her short stories, Flannery OConnor attempts to make her characters realize their pride and overcome it. In A Good Man is Hard to Find, the grandmother is a typical Southern lady. This constant effort to present herself a Southern lady is where her

I had only come to America to make a small fortune †Creative Writing Free Essays

Today was not a good day for me. Not many days are. It started out a warm day. We will write a custom essay sample on I had only come to America to make a small fortune – Creative Writing or any similar topic only for you Order Now The sun was shining and people where getting on with their lives, drive-bys, robbing banks and the normal nine to five jobs that where available. I don’t live in a particularly nice place, Harlem, but at the moment I could only afford to live there. I walked out of my small one bedroom, cramped flat onto the busy street and was on the way to the bus stop to get to work when two people came out of nowhere and attacked me. They stole my wallet and ran away. After about five minutes I limped up off the floor and continued my journey to work. After that it was a slow and painful walk but I eventually reached the bus stop. The bus arrived and I got on. I had to push my way to the back and had to stand up at the back of the bus because there wasn’t a free seat available. I glanced down at my watch and realised that I was already five minutes late for work. I had to try so hard to find a job and I didn’t want to loose this one and go back to living on the streets. Most people didn’t want to hire a black person to even clean the dishes at a restaurant. There was always the option of cleaning the streets but I had only come to America to make a small fortune then I would have gone back home. But now I realise that life doesn’t always turn out as you expected to. I worked in a small cafi. I didn’t make much there but I could live off it. I got off the bus in a rush and ran down the street as fast as my legs could carry me, ignoring the pain I was still in. The cafi I worked in was two blocks away from the bus stop so I was still quite far away from it. I finally reached it. It was a small white building, which, was really in need of a clean and a paint job. I ran in the back door and started to get changed. My boss was standing at the door and he looked quite angry. I slowly walked up to him and apologised for being late. All I could think about was what he was going to say to me. He had been the only person to give me a chance to work. I tried to apologise to him but he just told me to get my stuff and go home. I decided to walk back home. All I could think about was how back home in the morning you would wake up to the sound of the waves hitting the rocks and the smell of the salt from the sea. I thought about how friendly the people where there and missed the simplicity of life. I thought about the sun setting on the beach and listening to the sea slop around calmly over the gold and silver sand. How at night you can smell the fresh sea air intertwined with the smells of the foods that people had prepared earlier for themselves , carried with the smell of the pure reefer that you got there, not the chemical stuff that you get in Harlem , that’s sold on the street corners by the dealers. Then I thought about my home there. I wasn’t much but to me it was more than I have in Harlem. It was a little wooden hut. I continued to comfort myself as I solemnly walked back to my apartment. As I walked across a road a man stuck out his leg and tripped me over. I saw the man walk off and cars swerved around me trying not to run me over. I quickly got up and started to run home. I tried to avoid anyone I could see so that my journey back would be quicker. I knew that I was quite close to my apartment so I hurried even more. I finally arrived and as I walked up the stairs people where staring at me. I got inside and felt so depressed. It was the type of feeling when your goalkeeper gets sent off in the 18th minute of the champion’s league final. Now all I want to do is go back to Jamaica and see my family but I cant afford it so all I have left is my memories of the past. How to cite I had only come to America to make a small fortune – Creative Writing, Papers