Tuesday, October 30, 2012

Why do we have know this?


by akshiv, This post was originally posted at Future Science Leaders Researchers 2012 Cool Science.

­I was sitting in chemistry class learning about the triple point of a substance. This is a specific pressure and temperature point where the substance exists in all three states at once. From the back of the class, I heard a some growling about how knowing this subject matter would never, ever be useful in life. Where pray tell would we have to know how to liquefy gases at temperatures? I am going to ignore the obvious daily examples of this phenomenon, like in propane tanks, and instead focus on of the greatest applications of this knowledge.


It has been known for a long time that gases liquefy under pressure, but until Wernher von Braun, it had not really been applied. All right, all the historians are now mad at me. I have both glorified someone responsible for killing thousands of allied troops in the Second World War and I have said the refrigeration was not that important. The advent of refrigeration by the use of liquefied gas was an important point in history; I just think Wernher von Braun’s invention was more important.


So von Braun’s big invention was the ballistic missile and then the Saturn V launch vehicle. If the Saturn V rings a bell, it’s a good thing. That was the launch vehicle that was used in the Apollo program to allow astronauts to escape Earth’s gravity. To do this, it needed to create an unprecedented amount of thrust. One of the most explosive gases is hydrogen, and the gas that is needed to allow combustion to continue is oxygen. The problem is getting these gases in big enough quantities to safely ignite them under a rocket.


Luckily for the United States, von Braun has paying attention during his chemistry classes, and he understood that he could force gases to liquefy by subjecting them to high pressures. This way he created a safe method of creating a hydrogen explosion. Keeping the gases as liquids until he needed them, he let a correct amount become a gas and then combust, creating unimaginable amounts of thrust. The storage of the gases as liquids also allowed him to put a lot more fuel in the same volume so that a greater amount of thrust could be generated.


So next time you are sitting in class wondering why we have to know something, give the question some real thought. You never know what the answer may be, from the humble propane barbeque to the revolutionary Apollo Space Program.




About this contributor: I am in my final year of high school. I love playing ultimate frisbee, skiing and playing the clarinet/guitar. I am happiest when learning random trivia or stargazing. Learning for me is its own reward whether it is about the quantumly tiny or the cosmologically large.

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