About Chris Riley

I'm a middle school science teacher in New Jersey.

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.

Visualizing Time

Humans have trouble understanding very large and very small quantities. Stuff over a million, or smaller than 1/1000th is just difficult for us to conceptualize. For example, we tend to think that a billion isn’t that much bigger than a million. But there are 1000 millions in a billion.

Likewise, our understanding of time and how long ago things happened is kind of fuzzy. Here is a great visualization of time. (there are some naughty words in there, beware if you are of timid sensibilities)

One thing that I found surprising is that Cleopatra is closer in time to us now, than she is to when the Egyptian pyramids were built.

What Google’s cars can teach us

Google’s autonomous cars can teach us a lot of things. This Lifehacker article gives good hints on what kinds of things we should be learning from our soon-to-be codrivers.

  1. Pay attention to where others are going, and how fast they are moving. This will help you to anticipate your future moves. And it doesn’t only apply to cars. If you see that a bicyclist is approaching a parked car, you know that they will be moving over. Make room for them or slow down.
  2. Turn signals are helpful, but don’t trust that the other driver is using them properly. I know that I’ve forgotten to cancel mine sometimes, or turn it on too soon. But it helps to anticipate what the other driver will probably do soon, including moving into your lane.
  3. Maintain proper following distance. You should be keeping 3 seconds of distance between you and the car in front of you, so you can react and slow down if needed. Many times other drivers will move into this space. Don’t get upset about this. Just give enough space again. Personally, I like to go a little slower than the prevailing traffic on the highway. This makes driving much less stressful. The difference in timing is minimal, and the reduced hassles more than makes up for it.

The autonomous cars will be “driving like a grandma”, that is, playing it safe. This can upset us, but it really is better to be driving this way. Life isn’t a race. If we treat it as one, we place ourselves, and others, in danger.