# Conservation of Energy - Physics 1 Paper Topic Help

• Pcrouse
In summary, a student in a calculus-based physics 1 class was assigned a 4-5 page paper on conservation of energy. The student, who is an astronomy/mathematics major, was struggling to find a topic related to astronomy to write about. Some suggestions were given, such as the fixed amount of energy in the expanding universe and the non-conservation of energy in the redshift of light from distant quasars. Another suggestion was to discuss the energy conservation phases in supernova blast waves. The possibility of analyzing a perpetual motion machine was also mentioned.
Pcrouse
In my calculus bases physics 1 class our teacher assigned us a 4-5 page paper on conservation of energy. He said to talk about a specific topic of our choosing that had to do with conservation of energy. I'm an astronomy/mathematics major, and I was hoping somebody could help me decide on a topic. I really want to do something on astronomy, but I can't seem to find anything that I could write that much about.

Thank you,
Pcrouse

Newton's vis viva equation.

A physics class assigned a paper? One of the reasons I am doing physics is because I don't have to write papers!

You could talk about how our universe supposedly has a fixed amount of energy but is increasing its expansion. Or maybe how we are able to only see some really small percentage of the amount of "stuff" in the universe.

My suggestion is for the subject of Astrophysics, not Astronomy. Examine how the energy of radiation is NOT always conserved. Light emitted by a distant quasar is redshifted while traveling for billions of years so that longer wavelengths (lower energy) arrive here at our detectors. So what happened to that difference in energy?

For example, see lots of threads right here in PF on this.

Or do a paper on supernova blast waves, and describe what are called the "energy conserving" phase (the "Sedov" phase) and the "momentum conserving" phase (the "snowplow" phase). This may sound technical, but the physics is very simple, and it is interesting that we use language like that even though energy and momentum are always conserved quantities (outside of general relativity, where we don't have a concept of a global inertial reference frame in which to conserve energy and the situation gets pretty technical to say the least). In a nutshell, whenever we say energy is not conserved, we really mean it is going into some form we are not tracking (often heat, or in the supernova case, light from the shocked gas). That might be an interesting tack to take for a paper in any event-- consider some astronomical context where it appears that energy is not being conserved by the behavior witnessed, and then dig a little deeper to figure out where the energy really went to recover the concept of conservation of energy (again avoiding GR!).

Ken, the OP is a freshman.

It's OK, the energy conserving phase of a supernova blast is nothing but the energy in an ideal gas, given the rate that new gas is piled up into the expanding bubble. I think they can handle that! They are in calculus-based physics, no need to baby them! They don't even need to consider how fast the bubble expands, they can just ask what the temperature inside is, relative to the amount of mass in there. In the "energy-conserving phase", the temperature is inversely proportional to the amount of gas piled up in the bubble, but after that phase is over (the "momentum-conserving phase"), the temperature is much lower than that (because of the light that has escaped from the bubble). That's all there is to it.

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Analyze a perpetual motion machine.

khemist said:
A physics class assigned a paper? One of the reasons I am doing physics is because I don't have to write papers!

Yes, because physicists never have to write papers in their jobs.

If only I could write more papers on my job! Writing a paper for a journal or a conference is a kinda fun. Instead almost all of my writing is in the form of progress reports, proposals, briefing charts, technical reports, documentation, ...

## 1. What is the law of conservation of energy?

The law of conservation of energy states that energy cannot be created or destroyed, but can only be transformed from one form to another. This means that the total energy of a closed system remains constant over time.

## 2. How does the law of conservation of energy apply to physics?

The law of conservation of energy is a fundamental principle in physics that is used to describe the behavior of energy in various systems. It is used to explain the relationship between potential and kinetic energy, as well as the transfer of energy between different objects or systems.

## 3. What are some examples of conservation of energy in everyday life?

There are many examples of conservation of energy in everyday life, such as a swinging pendulum, a bouncing ball, or a rolling car. In all of these examples, the total energy of the system remains constant, even as the energy is transformed from one form to another.

## 4. How does the conservation of energy relate to sustainability and environmentalism?

The law of conservation of energy is closely related to sustainability and environmentalism because it emphasizes the importance of using energy efficiently and reducing waste. By conserving energy, we can reduce our impact on the environment and promote sustainable practices.

## 5. Are there any exceptions to the law of conservation of energy?

While the law of conservation of energy is a fundamental principle in physics, there are some exceptions in certain scenarios. For example, in nuclear reactions, a small amount of mass can be converted into energy. However, these exceptions are rare and do not undermine the overall validity of the law of conservation of energy.

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