AllMyFriendsAreDangerous

Forgive my initial negativity upon joining. Admittedly, I was a bit discouraged seeing more politics as it is already everywhere on the web. It was not my intention to jump on your forum and start judging it, merely a comment out of frustration. It is clear to me that there are valid points on any side of a political debate, but too many people take them personally and, before you know it, people begin to judge others permanently for a few differing ideals rather than for who they truly are. Politics causes more hatred among people than anything on this planet and I was simply saddened by the fact such nonsense found its way into a scientifically educational forum. Again, didn't mean to stir the pot...

A constant volume calorimeter simply uses a constant volume to resist the increase in pressure due to the formation of combustion gasses from the original solid. The expansion of these gasses will cause the gasses to cool and therefore take away from the measured temperature change. Keeping the combustion gasses at a constant volume keeps the gasses from cooling via the Joule-Thompson effect and provides for a better measurement. The energy here is not coming from taking a solid and making it occupy a larger volume as a gas, the energy here comes from chemically changing the material by reacting it with oxygen. The measured quantity here is the enthalpy of reaction and has nothing to do with the potential for work done by the expansion of the gasses.

iNow, I appreciate the the spelling correction and will resist the urge to correct your grammatical use of commas, after all, I am not "reasonable" intelligent, I am reasonably intelligent. MacSwell, thanks for the welcome.

Its always nice to jump on a science forum and see the activity stream filled, mostly, with politics. If we read the Politics topic, we see under it "....and how it relates to science". I almost wonder how much of it spills over into this side of the internet community by design. Facebook and Youtube are full of posts and comments designed purely to insight anger and frustration amongst a common people and the ignorance of those people rapidly takes over. Foreign entities intent on having us destroy ourselves clearly have the "science" of it figured out. Democrat vs republican, white vs black, police department funding, etc etc etc ~ none of it belongs here.

I had 3 different cell mates over the course of 6 years that killed their wives with hammers. I want hammer control! Thanks to drunk drivers who are obviously not to blame, vehicles kill thousands every year. Don't be complacent in these countless deaths, turn over your deadly vehicles IMMEDIATELY!

Go out into a forest of deciduous trees and find an old decomposing tree stump and dig up as much of the underground portion and roots as possible. When I was young, we cleared the land for a cabin and that night, the tree roots glowed in the dark (no joke). Turns out, phosphorus accumulates in tree roots. Plus, the decomposing stump usually helps with drainage, feeds the worms with organic material, and offers a bit of visual character to the soil. Nitrogen can come from anything green (like grass clippings - mind the seeds and weeds that propagate from clippings though) or you can even add a little pee. As stated above, sea weed is great too. Hard wood ashes are very high in potassium, just mind your pH levels (it is a base). I would be concerned about micro-nutrients as well..... I recommend the swiss method of preparing potassium nitrate, you get the N and K from pee and ashes without peeing on the garden or messing up the pH and just use the rotten tree stump as P

Superglue gets hard when water is applied lol, but i think he meant to ask if there are substances that get hard in warm water and soft in cold water.

Ethanol is just as good of a disinfectant as rubbing alcohol, so why bother? Assuming it was for disinfectant purposes anyhow... As for homemade disinfectants, you could also try electrolyzing salt and making your own bleach! When SHTF, you are better off making your own moonshine and using that to sanitize things. And for using alcohol to disinfect things, you dont want the super concentrated variety. Many people go straight for the 91% isopropyl. The best concentration for killing germs in in the high 60's to low 70's as the water prevents the alcohol from evaporating immediately. It takes a moment for alcohol to do its thing, so if you rub 91% on something, its likely to evaporate before it penetrates into crevices and do its thing. You'll know its the right concentration when it feels slippery compared to the 91%. All of this is moot anyhow as the stores are back in supply of these things. Of course you can make isopropyl out of ethyl alcohol, you just won't find anyone doing it at home. Make your ethanol anhydrous by azeotropic distillation with benzene then pass the ethanol vapors over a hot copper catalyst in a ceramic tube (not heating the tube till you purge the tube with ethanol vapor to remove oxygen lol) and pass the resulting acetaldehyde/H2 vapor into an ether/THF solution of methyl lithium and hydrolyze then distill the addition product lol. You can make it out of acetone too via the Meerwein–Ponndorf–Verley reduction. Acetone is an industrial byproduct of phenol production and is widely available. You can also make acetone using chalk and vinegar, but why bother... This all will cost you WAY more to make than to buy, unless it is the experience you are paying for.