Self serving biases and your own knowledge

How much do you know? Really? That much? Are you sure?

It turns out that there are lots of ways to think that you know more than you really do. Here’s a good scischow youtube about it. One of my favorites is the Dunning-Kruger Effect, which I see lots of. Basically, the less you know about something, the more you think you know. As a teacher I see this when students think they understand the topic, but then proceed to bomb the test. It works like this: When you have a beginners knowledge of something, you don’t know the intricacies of it. You don’t know just how much more there is to know.

I teach middle school science, so the material has been simplified—there’s a lot more to it than what I teach. Some students don’t get the simplified version, and they think that what they’ve gotten (the very simplified) is easy. Then they have to take a test on what they should know, and they have trouble with it. And when they get to a question on higher-order thinking skills … watch out!

The thing is, I think they could do much better. But when they’re studying, they think they know it, so they don’t study much. If they understood how much more they need to know, I think they’d realize that they needed to study more.

Anyway, watch the video.

Large numbers are hard to understand

Lots of people have a blind spot for numbers. Especially large numbers, like a million or a billion. Lots of people think that numbers like a million, a billion, and a trillion are evenly spaced on the number line, like 1, 2, and 3 are. But the amount of space between a million and a billion dwarfs the distance from 1 to a million. A billion is a thousand millions.

Here’s another way to look at it. It takes about 12 days for 1,000,000 seconds to elapse. But it takes about 32 years for 1,000,000,000 seconds to elapse. They are so far apart. But most people just stop thinking about what these numbers really mean, and kind of lump a million and a billion together. Kind of like “they’re big numbers, and a billion is bigger than a million”. Well, yes, that’s true. But it loses how much bigger, and it’s a lot.

Save lives for under a buck

A previous student of mine showed me this video, which actually ties in with something I had just found out about a few weeks previously. By combining a cheap, paper microscope that cost about $0.50 to make, and a child’s spinning toy, it is possible to diagnose malaria, which kills millions each year. The microscope is called the Foldscope. It’s printed on a heavy piece of die-cut paper, and then gets cut out and folded into a surprisingly powerful microscope, able to see blood cells. You can preorder these yourself (I have!). The other piece, the spinning toy, replaces expensive centrifuges to separate the blood into components. Coupled together (along with a doctor) you can do the lab work for diagnosing malaria for under $1.

Antibacterial dragonflys

There are a number of things that are naturally antibacterial. Silver, for one. For a long time, people have been using silver in things to help stop diseases. There’s also dragonfly wings. Now, scientists are making surfaces similar to the dragonfly wings to destroy bacteria. These are called nano-textured surfaces (NTS) and might lead to new materials that help prevent diseases.

One way that Math and Science are linked

Everytime math comes into my science class, the students always groan. “Why do we have to do math? We already had math class?” But math and science are linked. In fact, the math has to be there. And it can be really interesting how this happens. A number of years ago, one of my favorite youtubers did a trilogy of videos on this.

The first is on Fibonacci numbers, which seem to pop up all over the place. This then leads to one of my favorite irrational numbers: Phi (Φ). Everyone knows about Pi, but phi is pretty awesome too. Well, actually the golden ratio, which is also used all over the place, and mathematicians use phi as shorthand, kind of like they use pi for the ratio of the circumference of a circle to the diameter.

It turns out that when plants want to grow leaves, but not have the upper leaves be right above the lower leaves, they frequently put the leaves phi degrees away from the previous leaf. How do they do that? It’s not like they have protractors know about geometry or anything. It turns out that it’s really simple, as vihart gets to. It’s just growing where there’s more protein that tells the plant where to grow new leaves. This automatically ends up with the leaves being phi degrees apart. It’s really cool!

Anyway, here are the videos:

First agriculture

Ah, agriculture. That wonderful way of raising crops. Started about 10,000 years ago.

Or did it?

It turns out that humans aren’t the only one’s who raise crops for food. Ants have been doing it for much longer. On particular ant, Philidris nagasau, doesn’t just eat a particular fungus, but when an ant colony splits, they carry a start of the fungus to the new location. They’ve been doing it for over 8 million years, much longer than Homo sapiens has been around.

Food myths

Lifehacker just did an article on Food Myths. That is, things that people think are true, but aren’t. The full article explains each. Here are the myths:

  1. Myth: Eat a hearty breakfast, first thing in the morning.
  2. Myth: You need small meals every 2-3 hours.
  3. Myth: You need to eat immediately after a workout.
  4. Myth: You need to stop eating a few hours before bedtime.