The Sweetest Experiment – Chocolate and Solvents
Grade Levels: 3 - 8
The town of Hershey, Pennsylvania, has a slogan in which it claims to be the sweetest place on earth. That may or may not be true, but one thing is certain. The chocolate that is made in Hershey, Pennsylvania, sure is sweet, and that's part of why you'll love this science experiment.
Do you ever make hot chocolate from the powdered hot chocolate mix? You heat a cup of water or milk in the microwave, and then put the powder into the hot liquid, right? When the powder dissolves, you've got hot chocolate.
The water or milk in your cup is the solvent, and the powder that you pour into the cup is the solute. Briefly, a solute is something that gets dissolved. A solvent, on the other hand, is the substance in which the solute is dissolved.
In this, the sweetest of all experiments, you're going to test three methods of dissolving chocolate candy, such as a Hershey's Kiss. All you'll need is three Hershey's Kisses, or a similar, soft candy, your mouth, a clock or watch, and paper and pencil.
The first step of the experiment is to simply place the candy in your mouth and do nothing. Don't move your tongue around in your mouth, and, whatever you do, don't chew. You're letting the saliva in your mouth act as the solvent-the material in which the candy solute will eventually dissolve.
The only real work in this part is that you've got to note the time that the candy goes into your mouth, and the time at which the candy has completely dissolved.
For the second step, put the candy in your mouth, noting the time. This time, you can move your tongue around in your mouth, sort of pushing the candy from side to side. Do not chew. When the candy has completely dissolved, record your time.
With the third piece of candy, record the time that you put it in your mouth, and then go ahead and chew the candy until it's gone. Mark down the time at which the entire piece had dissolved.
It probably will be no surprise to you that the piece of candy you chewed dissolved the fastest, and that the piece that just sat in your mouth took the most time of the three to dissolve. This is because moving the candy around in your mouth exposed more of the surface area to the solvent (your saliva) than when the candy was just sitting still in your mouth. Just like with the hot chocolate mix, the candy dissolved by spreading out evenly in the solvent.
If you think about making hot chocolate, you'll realize that the process is more successful when you stir the powder in the milk or water instead of just pouring it in and letting it sit there. That's because stirring spreads the solute evenly in the solvent.
So you see, science doesn't have to be at all boring or dry – it can be exciting and lots of fun. Science is a living, always expanding field, and is important to every aspect of our lives. We all rely on science for our food, our health, and our very lives.
Excerpted from The Complete Idiot's Guide to Science Fair Projects © 2003 by Nancy K. O'Leary and Susan Shelly. All rights reserved including the right of reproduction in whole or in part in any form. Used by arrangement with Alpha Books, a member of Penguin Group (USA) Inc.
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