If you’re a middle school student at TASIS, you probably know these two guys in the photograph at right. What you probably didn’t know, however, is that they have been at the center of much controversy in this week’s E period science. The controversy is about the initial results of their ICE (to) WATER investigation. As all of you reading this Blog know, all 4 of Mr. M’s classes have been trying to determine if an ice cube has the same mass once it melts and turns into its liquid state. In other words, how much mass will (for example) a 5 g ice cube have once it turns completely into liquid water? Will it have more than 5 g? Less than 5 g? Or exactly 5 g?
The first time our classes melted their ice cubes to answer the mass question our results were very interesting…but also confusing. You can see the data for all 4 classes HERE. As you remember, nearly every group either lost or gained mass by the time their ice cube has finally melted. Well, that is, except for Luis and Angelo. They claimed that the mass of their solid ice cube and melted ice cube was exactly the same! Yet, not a single other group in each of the 4 classes got the same results! Some people (ahem, all of their classmates in E period) accused them of falsifying the results of their experiment! And so, a genuine controversy was born…
In class on Tuesday–but only after writing a detailed Method/Procedure designed to eliminate both human and equipment errors–every class had an opportunity to perform the ICE to WATER investigation a 2nd time (and in some cases a 3rd time) . You can see the latest data for all 4 classes HERE.
For Angelo and Luis, who maintained that they did their original experiment carefully and without error, this day was an important moment. They put their bag containing 14.1 grams of liquid water–which they generated from melting 14.1 grams of ice during the first investigation–in the freezer. They left it there overnight and predicted that it would have the same mass–exactly 14.1 grams–in its new frozen form. Did it? Yes, it did, and this time everyone in the class watched them put it on the electronic balance to make sure they were being honest and accurate. Feeling confident, they then offered to let the water melt back into its liquid form in front of the whole class. Again, they predicted that it would have the same mass–exactly 14.1 grams–in its liquid form. Did it? Yes, indeed it did. Thus, they proved that–when executing careful experimental procedures–water can go from solid to liquid to solid and back to liquid without losing any mass! As you can see in the photo at right, this was enough to make their classmates bow down to their technical expertise.
All hail Luis and Angelo! The new masters of experimental technique.