Since the school science fair is safely behind us, we can give you a peek at the projects the Free-Ride offspring presented. (We couldn’t do this prior to the science fair without running the risk that the sprogs would be accused of lifting their projects from a blog post.)
Here’s the elder Free-Ride offspring’s project board (or at least the central panel of it):
Originally, the idea was just to grow different kinds of crystals and draw some conclusions on why different types of substance grow the kinds of crystals that they do. However, that was deemed not sufficiently quantitative. So, the project shifted a little:
The elder Free-Ride offspring decided to compare crystals grown from saturated solutions (where the solution couldn’t hold any more dissolved material than it already does) with those grown from weaker solutions. Because we had plenty of sugar and salt in the house, those were the two substances used to make solutions for the comparison.
Judging from the preliminary experiments, vitamin C crystals would have been prettier, but we didn’t have a five pound bag of vitamin C sitting around.
The results, from my point of view, were nice ones because while they kind of fit with the elder Free-Ride offspring’s hypothesis, they also complicated it. More crystals grew from the saturated salt solution than from the weaker salt solution. But in the same time interval (a matter of days), neither the saturated sugar solution nor the weaker sugar solution grew any crystals.
I like a result where you have to think hard about plausible explanations. It forces you to learn more than you were planning to learn.
The younger Free-Ride offspring’s science fair project followed up on earlier experiments we had conducted for fun last spring.
But when you’re trying to dissolve avocados for a science fair, you need to be a little more rigorous than when you’re just trying to dissolve them for fun. So, we needed to think of what we could observe that could give us a clue about whether any part of the avocado had actually gone into solution in any of the solvents we tried.
The plan involved decanting liquid from each of the (liquid + avocado) tubes and comparing that liquid to avocado-less solvents. The comparisons included look, smell, taste, and what color the liquid turned when we added some red cabbage indicator. Without high tech analytical instrumentation, this seemed like a reasonable number of things to measure. (I’m relieved that we didn’t have to load columns in the kitchen.)
You’ll note that I had to step up on the taste-test for the vodka with and without avocado. Lab safety considerations when the PI is an eight-year-old.
We have not yet devised the aqua regia that will completely dissolve an avocado. But science is like that sometimes.