Today I was leading my students in an experiment that would reveal "the rule for what floats." We had previously floated (or sank) various objects in regular, room temperature tap water. I then weighed out 100 grams each of sugar and water, mixed them together and weighed them again. To my surprise, instead of having 200 grams of sugar water solution, I had 125 grams. At first I thought we had not tared our scale properly, so I poured the mixture into a newly tared beaker. We still came up 75 grams short. We then weighed out another 100 grams each of sugar and water. This time I tared the beaker containing the water back to 0.0 grams and then poured the newly weighed 100 grams of sugar directly into the water as it was on the scale. It only increased the weight by 25 grams. Then I thought there was something wrong with how the scale tared the beaker and weighed the beaker separately. It weighed about 115 grams, so this could not account for the loss. Given that you cannot destroy matter, can someone help me understand why adding the water to the sugar in equal weight resulted in a mixture that weighed less than 200 grams?? I'm flummoxed and I can't seem to find an explanation on the internet. I promised my students I would try to figure out why this happened.