Science questions not worth a thread I: I'm a moron!

Cutlass said:

So I was thinking about this idea of using a Sterling cycle engine for power generation. I've read that the Sterling cycle works most efficiently where there is a large temperature differential available. That would mean that in the tropics it would be at a disadvantage, say if a solar concentrator were providing the heat while ambient air provided the cooling. But what about islands near deep water? Hawaii for example produces much of its electricity from imported oil and coal. But it's also located in some very deep ocean waters. So what if we used the horizontal drilling technology to tap that deep ocean cold water to provide the cooling? Could we cost effectively power an island that way?

Click to expand...

For OTEC to be viable as a power source, the technology must have tax and subsidy treatment similar to competing energy sources. Because OTEC systems have not yet been widely deployed, cost estimates are uncertain. One study estimates power generation costs as low as US $0.07 per kilowatt-hour, compared with $0.05 - $0.07 for subsidized wind systems.

Click to expand...

Atticus said:

Let's suppose there's a measurable thing A, and people generally think that it's value is a. For example it could be the average height of adults or correlation between smoking and lung cancer.

Let's furthermore suppose that a actually is the correct value and there are 100 people researching the thing claiming that it isn't, that the real a is bigger. They all conduct research on the matter, and naturally, you'd expect five researches to conclude that the null hypotheses false with p<=0.05. They send papers on their research to "American A research bulletin", and they get publishded, whereas the 95 of the researches just keep their mouth shut (perhaps because of their own convinction, they believe their research that didn't reject the null hypthesis was faulty).

Is a phenomenon similar to this an actual problem? Is there some smart ways it is fought against?

Click to expand...

A Swedish study in 1992 tried to determine whether or not power lines caused some kind of poor health effects. The researchers surveyed everyone living within 300 meters of high-voltage power lines over a 25-year period and looked for statistically significant increases in rates of over 800 ailments. The study found that the incidence of childhood leukemia was four times higher among those that lived closest to the power lines, and it spurred calls to action by the Swedish government. The problem with the conclusion, however, was that they failed to compensate for the look-elsewhere effect; in any collection of 800 random samples, it is likely that at least one will be at least 3 standard deviations above the expected value, by chance alone. Subsequent studies failed to show any links between power lines and childhood leukemia, neither in causation nor even in correlation.

Click to expand...

We have learned a lot from experience about how to handle some of the ways we fool ourselves. One example: Millikan measured the charge on an electron by an experiment with falling oil drops, and got an answer which we now know not to be quite right. It's a little bit off because he had the incorrect value for the viscosity of air. It's interesting to look at the history of measurements of the charge of an electron, after Millikan. If you plot them as a function of time, you find that one is a little bit bigger than Millikan's, and the next one's a little bit bigger than that, and the next one's a little bit bigger than that, until finally they settle down to a number which is higher.

Why didn't they discover the new number was higher right away? It's a thing that scientists are ashamed of--this history--because it's apparent that people did things like this: When they got a number that was too high above Millikan's, they thought something must be wrong--and they would look for and find a reason why something might be wrong. When they got a number close to Millikan's value they didn't look so hard. And so they eliminated the numbers that were too far off, and did other things like that. We've learned those tricks nowadays, and now we don't have that kind of a disease.

Click to expand...

Flying Pig said:

More often what happens is that Company A commissions 100 studies, picks out the five that connect it with some benefit that they want to claim, and write an advertisment saying 'studies show that our product is linked with this benefit'. By the time anyone corrects them, the advert's already out there and people are already buying it.

Click to expand...