I have a large number of hot bath's and I stay in them upwards of an hour; during that time I sweat a lot(on the basis that my forehead is sweaty and salty) and after my bath I also sweat.

What I want to know is how much salt is excreted during an hour long bath, I know this will also be based upon my physiology(30,male,normal weight) but is there any standard a little like when you burn calories when doing a certain activity.

Also our of interest does having a bath increase the amount of calories you burn?  

Too much salt kills most plants. How much of the salt put onto roads each winter ends up in rivers or the soil, and does it have any noticeable impact on wildlife and crops?

I've seen the animations of icy meteorites filling the primordial oceans with (presumably) pure water, but rocks are not naturally 'salty', in a potato crisp sense, and extracted salt is from dried-out deposits originally from seawater. And why Sodium Chloride in particular ? 

Recently, a friend of mine did his 8th grade science fair project. He decided to test whether pure water, water with flour in it, or water with salt in it would evaporate (and thus be purified) the fastest. He found that the flour went the fastest, the salt was next, and the pure water was actually the slowest. He did say that he used the same volume of total liquid overall, not just the same volume of water, so that could have been a factor by decreasing how much needed to be evaporated. But the margin was too large for this to be the only factor. Does anyone know why this would happen?

Back in school we were told how you can seperate salt and (powdered) pepper using static electricity. Someone asked if there was a way to seperate salt and sugar. The teacher didn't know. Since then, no one I asked has come up with anything better than sorting the crystals by shape under a microscope. Melting temperatures are very different, of course, but sugar caremelises before melting decently. Both are soluble in water. But maybe there still is a way? What about solubility in organic liquids?

Scaling up culinary recipes does not always follow a linear relationship, especially when using spices, salt or alcohol.

For example, for 1 litre of water you might be accustomed to adding 1 measure of salt, but for 4 litres you wouldn't add 4 measures of salt, but much less.

Does anyone know what the explanation for this is?

Cathy Fisch, Orsay, France