Dave Cell

The problem with hearing these "25 year" comments is that, as Inigo said, the 25 years never gets any smaller and they are never clear on if that means a reliable plant or an entire infrastructure. People have high expectations for reliability (at least in the US). We are very spoiled in this regard. I know how hard it is to keep conventional fossil fuel and nuclear plants running with almost no down time. I can't imagine the kind of reliability nightmare a fusion plant would represent.

What is the general thought on the space elevator concept? Is it really that far out there? I will start building the giant slingshot now.

I don't have much to add that others haven't said. However, I would caution you on your use of vocabulary in a scientific forum. I know people who would wig out if they heard you call water a fuel Just to reiterate: It takes more energy to separate hydrogen/oxygen from water than you will ever get out of it. Aside from price, we use fossil fuels because they already exist in mostly useful forms. On the other hand, this is also true of wind, solar, and hydro sources. Hydrogen is more of interest as an energy carrier (battery) than anything else. Using solar power to heat our homes and make hydrogen for stored power or automotive use is a nice idea, but it would be nowhere close to being as affordable and reliable as what we are running on now.

Hey everyone. I have an engineering background and I also supervise a science club at a local school. I'm trying to think of ways to relate my applied science knowledge to some more fundamental science in order to better represent the mathematicians and fundamentalists. I was thinking of explaining how a lot of engineering properties come from science and math. For example, in grad school I remember the prof deriving the specific heat of a gas from the M-B distribution. I'm somewhat ignorant regarding this since my field was in mechanics and we only ever really had to know what the M-B distribution was. Can anyone recommend a good reference for this? I managed to find online that I can also do this for thermal and electrical conductivities but I haven't seen these worked out either. I'm guessing the math is a bit too difficult for high school students but I'd like to work through it myself just so that I'm confident with it. Also, does anyone know how well these types of derived properties fit to experimental data? I welcome any other ideas you might have. I'm trying to stay away from electromagnetism, however, because we just had a big project on that. Thanks for any help. Dave

Light is a wave but the waves can only move in little packets called quanta, which we can treat as a particle at times since the wave would then only have a certain length. What I just said is not really true but if you accept it you will sleep well at night and have more time to watch TV.

I'm not sure I'm following you. If you are talking about an engineering application then do you mean you want to relate the rate of heat transfer through a structure (a fin, for example) while the heat transfer itself is significant enough to cause changes to the structure itself? If so, I can think of basic examples, such as the arms of a heat dissipative device shortening as it cools and therefore losing surface area. A problem like this is pretty straightforward, but this is never an issue since fins are not designed to chock heat flow and therefore the structural changes would have a negligible effect. A better example might be found in some grad texts on hot rolling and other common metalworking. I may be misunderstanding you. If you are talking about how products formed in, let's say combustion, affect the heat transfer based on their chemical structure, or some other micro level question, please disregard.