Day 3

Why try garlic? Surely, you must have seen the ads that claim garlic will cure you of anything and everything. They have been advertized for at least two hundred years. Plus we know garlic is safe for human consumption, even in high quantities - my college friends are a case in point. We even ate garlic ice cream thanks to a buddy of mine, Rob White. So is garlic the miracle cure? Let’s start by seeing what it does to bacteria.

The oil from wild sage is known locally as a bacteriacide - "kills germs". Why not test it!

So why yucca? (It is actually agave (Agave caribeaicola), but once you goof and say it wrong all day on television, you have to stick with your mistake. It is too hard to correct. This is reality TV after all.)

Agave, looks like a big aloe plant and it is also fairly closely related to aloe. Aloe is known to promote healing. That doesn’t mean it kills bacteria, but I was curious to see what it would do. These are long lived plants that seem to have few infections and blemishes on them.

We made three replicates. In other words, in order to have confidence in our results we tried everything three times, just in case one (or more) of our tries ended up strange. For example, what happens if I thought I dipped the pipette in the wild sage, but I actually dipped it in the yucca by accident and didn’t know it? The results for that plate would be inaccurate, but I wouldn’t know it. The liklihood of me doing the wrong thing three times is much less than if I only did one try of each thing. 'Minimizing the likelihood of errors' or 'improving accuracy' - that’s why we make replicates ('repeats').

Why did we use a control? What is a control anyway? I think of a control as what would happen if you didn’t do anything. In other words, we grew bacteria on agar plates with beef broth for bacteria food. If we didn’t put a bacteria-killer on the plates, what would we expect? (Tons of bacteria to grow.) A set of control plates with lots of bacteria lets us know that everything is going as it should. If the control plates didn’t have bacteria, then we’d know something was wrong with the agar, our sampling of bacteria from Mike B’s mouth, or something else. The important thing is that we wouldn’t make the mistake of saying all the treatments, garlic, wild sage oil, and agave, are great at killing bacteria. We’d know there wasn’t bacteria there in the first place.

Okay, so we have control plates to make sure everything is as expected and also to see what happens if you don’t add a treatment.

As it turns out, our results were pretty consistent among plates of each treatment (each thing we tried). The garlic was the best in all three of its plates, then the wild sage oil, then the agave, and then the control plates which were covered in bacteria.

Hey, this challenge worked out okay! And wasn’t Kathy’s microscope the coolest thing ever!

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