But it was nearly 100C when they started.
BTW How do you know it was 40C at the end? I didn't see a thermometer anywhere.

near vacuum the boiling point keeps going down with the pressure it's what is known as the vapour pressure. the higher the temperature, the higher the vapour pressure. when the vapour pressure of the liquid rises to the atmospheric pressure above the liquid then can evaporate in the middle of the liquid because it now has enough pressure to displace the liquid against the pressure of the atmosphere trying to squeeze it together and collapse them. When you boil a pot of water the water at the bottom of the pot reaches 100C before the water near the top. water at 100C has a vapour pressure of about 15psi or 1 atmoshere so bubles of water vapour form. the bubbles start to rise and encounter water that is only 99C and the vapour cools and it vapour pressure drops to just below 1 atm it condenses into the 99C water (giving off it heat of varourization and heating up the 99C water allowing the next bubble to rise a little higher before in collapses) I don't know what the vapour pressure of water at 20C is but I would imagine it's not much more that about 0.2 atm That's fairly close to a vacuum Gordie

Wow, thats the best description so far. I was a little confused about how this actually worked. I am wondering, can this method then be used to create a Near Vacume for other experiements? For instance holding a container over a large amount of steam which has lids for the top and the bottom, and quickly closing it off on both ends while it is full of steam. Seems like that might work......Im not sure how I could get anything into it however without letting in more air, but It might be possible-for instance to somehow creatively mount whatever you need inside the chamber first, as long as it would not be effected by the heat of the steam. Am I missing a concept here or could this work to create a poor mans NV.

Sorry I took so long to notice your question.

DISCLAIMER: This is a workable concept. Weather it may be functional or dangerous would depend on materials.

If you want to use a bell jar, make a base with two holes in the bottom.
Place your specimen on a raised platform as there will be a layer of water at the bottom.
Holes need valves that are good enough to hold a vacuum (or near) and everything needs to withstand 100degC.
Attach a kettle to one valve and leave both valves open.
Place your specimen. Place the bell jar over it.
Turn on the kettle. There will be a rainstorm inside as the bell jar, base, and specimen heat up. This could take a while. Eventually the amount of water trickling out of the valves should slow and there should be steam billowing out of the exit valve.
Of course at this point EVERYTHING IS HOT ENOUGH TO GIVE YOU A NASTY BURN! (including the valves) Also by this point virtually all the air should have been replaced/displaced by steam.
Now close the valves and disconnect the kettle(so it doesn't blow up) and WAIT.
As everything cools down the steam will condense and the pressure will drop.
DON'T THROW ICE OR EVEN COLD WATER ON IT!
IT WOULD ALMOST CERTAINLY EXPLODE.
Once it gets to room temp you should have a pretty good vacuum.

Personally I would use a vacuum pump, but if circumstances make this easier for you then have fun and don't kill yourself.

Gordie.

what you do mean bad grammar is that?

no idea I has for you, I crazy think you must be.

crazy me? says you crazy me? dare how could do that you!

ungood Englishes you speak's? one excuse For bad grammaricles, there is. crazy you it is!!!!!!!!!!

me crazy? talking who look grammar bad it is! english me speak's perfect it is!!! tell me you grammar me bad yous worst grammar me than! unbad it is grammar me,grammar best is mine grammar yours worst it is and you spell ungood very,spell i have good very!

yoda would be proud.

I was thinking the same thing

true that

Soda what?

Is this guy mad!?!?!?! he is pouring water on the stove!!!!!

They are called " Hand boilers " They have ethyel alchohol in them that boils at room temp. I ordered some from stevespanglerscience.com

Actually, ethyl chloride or methyl chloride. Rather poisonous. but better physical properties. Gordie

The one I have is colored ethyl alchohol, where would i find one with those chems in it? My alchohol one bursted 0_0

I don't know where you are? If you are in or nar Toronto, Canada then you could go to Efston Science, near Dufferin and Hwy 401. Else you can go to their website at escience.ca and search for 'drinking bird'. If they cannot mail it to you then google 'Happy Drinking Bird' or 'Dippy Bird' or 'Drinking Duck' for something local to you. If you are just looking for the chemicals (excelent for making ethyl or methyl mercaptan) then you could try Toys R Us or dept stores for something called (I think) finger boilers. Little ecapsulated bublers on top of a pen. I have one concern... I heard a rumor years ago that the reason the birds disapeared was because the liquid inside was toxic. If your bird had ethanol in it, then it may be that all current related toys also use ethanol. Good luck! Gordie.

darn... im not in canada... and I think your concern is probably right. I do not think they make the hand boilers or drinking ducks from ethyl alch much anymore.

It depends on the type of glass used when they make glass they can add different elements to the glass to give it different property's , much like making a metal alloy if you use pirex glass ( the standard laboratory glass) the expansion due to a change in heat like this is not enough to crack the glass

they don't really add different elements, they simply vary the amounts of ingredients.. with pyrex, they add quite a bit more silica than household glassware, but that means that it has to be made by machine, as trying to work that type of glass manually would be near impossible...