Neato!

Jacob and I did the most neato-est experiment in Chemistry the other day! (I know, I know...a homeschooling mom shouldn't use the word "neato-est" but it's the best way I can describe it!) Anyway, the purpose of the experiment was to get a rough idea of how small a molecule really is. In order to do this, we followed a process to dilute 0.5 ML of dishwashing liquid to 400.0 ML. We filled a large bowl almost full of water and let it sit. We calibrated an eyedropper to determine how many ML of liquid are in each drop....this turned out to be 0.026 ML. Next we sprinkled a light dusting of pepper over the surface of the water in the large bowl. Then we carefully put one single drop of the diluted dishwashing liquid in the center of the water/pepper-filled bowl. The pepper that was in the center of the bowl was pushed outward, leaving a clear circle in the center (see picture below). Why did it create a clear circle? Glad you asked. :O) Because the dishwashing liquid is made of several compounds, one of which is sodium stearate. The other compounds sank to the bottom but the sodium stearate remained on top of the water, spreading out as a single, circular layer of molecules. Using the measurement of the clear circle in the water, and several other calculations we determined during the course of this experiment, we determined that the width of the molecules in the sodium stearate is about 1.2 x 10(to the negative 8 power) What does a number like this mean? Well, the width of the average human hair is about 10(to the negative two power) centimeters. The size of these molecules is about 100,000 times smaller than that! Pretty neat, huh? :O)