How do I make water evaporate in the oven?

Question

My son is doing a science project that calls for various water types in jars to be evaporated. It says that you may either leave the jars in the sun or for a faster approach, put the jars in the oven for a few hours at 200 degrees. They have been in there now for about three hours and not a drop of water is gone. Should I up the temperature or what?

Answer 1

You have to up the temperature to over 212 farenheight.  That is the temp that pure water boils.  You might want to "burb" the oven and just open and shut the door quickly to make sure pressure doesn't build up.  But it won't be a problem, unless you latch the door.  Depending on what is in the water, it will change the boiling point.  So, just to be sure, raise the temp to about 250 or so.  Also, it's very important to make sure the jars don't have a lid.  If they do, you'll blow up the jar.  That'd be bad.  

You should see the water with the salt in it start to boil after the pure water boils.

Again, don't put a lid on the jars.

Answer 2

Turn the temperature up and open the door a bit to make sure the hot humid air exchanges with outside less humid air.  The slow evaporation is because the air in a closed oven is saturated with water vapor and won't evaporate more.

Answer 3

leave the door open turn the grill up full and put water in a large wide dish under the grill

Answer 4

Leave it overnight. If you up the temperature above 212, the water will boil, and I don't think that is what the experiment wants. Even at 200, I bet is evaporates really slowly. You did leave the lid off the jar, right?

Oh, and I agree with the above answer. Leaving the door open a bit should make a difference.