Hi Kim- We've got a number of answers on this site discussing changing
water boiling and freezing points. You should be able to guess one
answer pretty easily- the effect of adding plain water!
As you take data here's some things you might want to look for:
1. When you change the amount of salt or sugar, etc. that you add,
how does that affect the change in the boiling or freezeing points?
Does twice as much solute (salt etc) have twice as big an effect?
2. Is there any connection between the effects on the boiling and
freezing points? When some solute makes a big difference for one, will
it make a big difference for the other as well?
Someday, you may take a beginning course on thermal physics, where
you can learn not only what sorts of effects to expect in these
experiments but also why to expect them. You can even get some
information about that on this site.
(published on 10/22/2007)