ScienceNostalgia101

Hmm... what about the fact that some of the thermal energy that would otherwise go toward increasing surface temperature instead goes toward boiling water? Would that decrease temperature while simultaneously increasing humidity? (Assuming some of the water vapour above each pot of food/coffee escaped into outdoor air before condensing?) As for me, I don't cook. I work in places that have food available and/or eat canned fish/frozen dinners/peanut butter sandwiches for protein. Perhaps not the healthiest approach, but it's what I'm used to.

What about enough heat to boil water for cooking food? That's useful even when it's warm. Also, if every household had a concave mirror for a rooftop, more sunlight would be absorbed by the boilers and less would be absorbed by anything else. Wouldn't that reduce the urban heat island effect? Could it also reduce the city's albedo to below what that of the pre-existing natural environment would have been? As for hail being not a big deal to solar panel rooftops, how come it's such a popular anti-solar talking point? Engineering angle aside, would replacing solar panels with concave mirrors do more good to the pro-solar movement or more harm from a PR standpoint? EDIT: And in light of Australia's wildfires, should I bump the "harnessing the energy of forest fires" thread or continue that discussion here?

A number of my past posts relate to hypothetical alternative sources of electrical power. I'm wondering if it'd be more efficient (pun intended) to coalesce them all into one megathread, such that people could compare and contrast these hypothetical proposals. I'd like to reiterate all these proposals, and a few new ones: A. One common criticism of household solar panel rooftops is that they're vulnerable to hail damage. I'm not sure if there's some way to mitigate this vulnerability that the fossil fuel industry doesn't want us to know or whatever, but in the meantime, since thermal solar isn't as vulnerable to hail damage, would a better approach be to have some rooftop concave mirror and/or rooftop convex/fresnel lens, to boil water? (This might also be more efficient twofold in having a direct source of heat, instead of having to convert heat into electricity and then electricity into heat.) If fire safety's the issue, would it be worthwhile to have the water supply BE the convex lens; namely, a watertight (apart from some outlet/intake tubes at the top) roof filled with water, such that the point of convergence is some dark surface within this roof that happens to be surrounded by water? B: So lightning is a form of direct current, is it not? If so, does that mean that some device designed to attract lightning, and run it through some electrolysis device, would be able to convert its electrical energy into chemical energy?

Forgot about this thread until now. Here's another one. At 6 minutes and about 20 seconds in, the fish claim they're going to "roll" the bags by swimming in water that's inside the bags. I guess the idea is that they're going to swim in a line that does not cross the center of mass, but that still leaves behind a question. If in swimming forward they push water backwards, is there any way for the torque they generate by this action force to not be cancelled out by the water-pushing reaction-force?

Subject came to mind again because of post-tropical storm Oscar. How expensive would any materials that can withstand hurricane force winds for the purposes of structures like these be? (For what it's worth, I accept that the "rows of wind turbines to prevent hurricane development" option is out of the question.)

Gah, I forgot all about the thermal effects of all that air resistance. Anyone know more about air resistance's effects on bullet acceleration?

Originally I was going to make this a "relative motion" thread, but I think the notion of analyzing movie physics is more interesting overall. In "Rat Race," a mechanic startled by the passing supersonic landspeeder fires a bullet parallel to its path. (At about a minute and a half into the clip.) To the drivers, however, the bullet appears to be suspended in mid-air, as it is moving at approximately the same velocity as the landspeeder. 1. Would the bullet's path be kept horizontal for any non-negligible amount of time by air resistance, or would the vertical component of its motion immediately assume downward acceleration like everything else? 2. How quickly would the horizontal component of its motion be slowed by air resistance? 3. Either way, would it be safe for the drivers of this landspeeder to reach out of the window and grab the bullet, provided they maintained the same velocity as the bullet while it was in contact with their hands?

https://www.nhc.noaa.gov/gtwo.php?basin=atlc&fdays=2 See, this is the kind of thing I was talking about earlier in the thread. Right now, off the coast of Cancun, Mexico, there's a storm brewing that has a 50-50 chance of developing further, on top of all the other storms the North American continent is about to face in the near future. Cancun is about 200km from the west coast of Cuba, while Key West, Florida, is about 150km north from Havana, Cuba. If we had rows of interconnected floating wind turbines along at least those stretches of ocean, to harvest the wind while it was still gale force, would at least somewhat cut down on hurricane development?

They're hundreds of kilometres wide... so definitely tens of thousands, probably hundreds of thousands, of square kilometres. How efficiently could offshore wind turbines be mass-manufactured in assembly lines if we took all possible money away from building any other type of power plant? (Ie. Coal, oil, natural gas, solar, geothermal, hydroelectric and nuclear?)

Bumping because of Hurricane Lane. (It's been a week and a day since the other post.) Another question now; if they had enough rows of offshore wind turbines, harvesting about 3/5 of the wind energy at every row, would they be able to prevent hurricanes from forming in the first place?

You mean something like this? That's kind of what I had in mind when I said "horizontal instead of vertical." I didn't mean the axis was horizontal, I meant the blades, instead of going up and down, went from N to E to S to W... or in the other direction, depending upon how the hurricane approaches it. As for other wind turbines, even if they have to shut down for full-blown hurricanes, doesn't that still mean they can sap the energy of developing hurricanes? (Ie. Ones that haven't yet achieved hurricane force winds but might not at all if wind turbines sap their energy sooner?)

Inspired by my own thread on forest fires. https://energyeducation.ca/encyclopedia/Betz_limit So basically, the Betz limit suggests that a theoretical maximum of 59.3% of energy could be extracted from wind at a time. That leaves 40.7% or more still in the wind. So, wind retains at least 0.407 times its maximum energy; which, by E=mvv/2, suggests it retains 0.638 of its speed. Does that mean that with a long enough row of closely-packed, highly-efficient wind turbines designed to handle hurricane-force winds, you could reduce the wind speeds from 120 km/h to about 77km/h, storing the excess energy until the power lines are repaired? Alternatively, what if one build a GIANT wind turbine... and/or made it horizontal instead of vertical. (Ie. Flat to the surface... or close-to-flat, given Earth's curvature.) If it were hundreds of kilometres wide, would any hurricane that passed through it turn horizontally aligned blades and convert the kinetic energy to storable electrical energy that way?