About Chris Riley

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

Circle Irrigation is Cool!

Sometimes when flying over the middle states, you might see something like this:

from water.usgs.gov

Some of the more comedic then say “Look! Crop Circles!” Well, yes, they are crops, and they are in circles, but these aren’t made of aliens. If you got down to the ground to view them close up, you’d see something like this:

Alibaba sells just about everything

So, how does that make the green circles? I’ve wanted to know more, and conveniently Destin at SmarterEveryDay just made this video that explains it really well:

Thanks for explaining all that Destin!

Necrobotics is using dead spiders as robotic hands

Spiders are awesome. If you’ve ever seen a dead spider you know that they curl up when they die. They do this because that’s the normal position for the legs; to keep the legs spread out the spider pushes fluid into the legs, which straightens them. Yes, spiders use hydraulics.

So some enterprising engineering people at Rice University decided to use a syringe to actuate this hydraulic system. And she can use it to pick stuff up and put it back down. It turns out that dead spiders can be used as robotic claws. Neat!

Deeper than the Kola Superdeep Borehole, and lots of power to boot

For years I’ve been fascinated by the deepest humans have ever dug into the Earth. The Kola Superdeep Borehole in the Kola peninsula of Russia is over 12 km deep. It took 20 years to dig that far, and they had to stop because it was so hot down there (180 °C) that the rock was plastic and flowed, making drilling nearly impossible. The project was stopped in 1995.

But it looks like scientists may have found a way to dig deeper holes, and use the great heat down there to generate power. We’ve been using geothermal power for a long time, but it hasn’t been feasible to do in where the surface crust isn’t hot. The really interesting thing is the way we may be able to drill deep, down to where it’s 500 °C.

Quaise, a spinoff from MIT, has a way to use millimeter-wave beam technology to easily and quickly break even the hardest rocks. They claim to be able to complete a 20 km deep hole in just over 100 days.

If this works (and that’s still a big if), it could lead to reliable geothermal power, without requiring CO2 emissions after the hole is dug. They’re looking to have a 100 megawatt geothermal plant operating in 2026.

History of Science

I’ve been learning about the History of Science courtesy of Crash Course. It’s really interesting.

I first found out that the history of science was fascinating from Connections by James Burke. This was a PBS series back in the day (the late 1970s) (and it’s not really PBS, since it came across the pond from the BBC), and each one traced a series of scientific and technological discoveries from ancient to modern times. The first episode traced the invention of the plough to modern power blackouts. While the show looks dated (hey, it’s over 40 years old!), if you can get past that, it really rewards viewing. You can watch it on YouTube here.

Anyway, the YouTube playlist for the Crash Course History of Science is 46 episodes long, so I have some watching ahead of me.

Well, I just finished it today. There’s a lot there to unpack. I think they did a really good job with it. I’m also watching their course on Outbreak Science, and I want to start watching Geography; I’ve always liked maps.

#crashcourse

4 different reading levels

Do you know how to read?

At this point, since you’re reading this, I expect so. But it turns out that there are different levels of reading, depending on your ability and what you’re trying to learn. Each level builds on the previous levell

Elementary Reading

This is the simplest level of reading, when you just want to know what this sentence says. This is what you’re doing when you’re learning a foreign language.

Inspectional Reading

This is used to find out what the book/article is about. It can be done with skimming or superficial reading.

Skimming is when you read the different headings to get a gist of the structure, then go back to the beginning and read the first few sentences in each paragraph. This will give you the overall idea of the article, but nothing like real understanding.

Superficial reading is when you just read. You read every word, one after another. This is what we usually do when reading for pleasure, so it’s probably what you’re most used to doing. But again, it isn’t really about understanding.

Analytical Reading

This is where we get into really thinking about what we’re reading, but it takes more time and effort. You ask questions about what you’re reading and organize your thoughts. You take notes on what you read; perhaps have a bit of debate with the author. You’ll understand the material much better.

But we’re still not done.

Syntopic Reading

Instead of reading just one book/article, read different ones from different points of view. You actively compare the different books, evaluating the evidence and analysis provided. This is the highest level, and the most demanding of both time and effort.

When reading in school, at least in middle school, it’s best to be doing Analytical Reading. Think about what is being said. What does it imply? Are there things that are missing or that you’re confused about? Write things down in your own words summarizing what the author said.

Terminal Velocity

Today I went skydiving with my son! First time for both of us. Until you’ve done lots of dives you have to go in tandem with an experienced skydiver. So we went to the Sussex Skydiving, and checked in. We each got hooked into one half of a tandem rig. Then we went up in the airplane to 14,000 feet (along with our instructors and the other people jumping). At that altitude the plane leveled off and pairs started jumping out.

First the instructor attaches you to their suit (the other half of the tandem rig). He tightens the straps so you’re up nice and snug, as one unit. Then we moved together to the open door, and I put my feet out. My instructor then pushed us out of the plane.

The first few seconds were somewhat disorienting, but I quickly got my bearings and started hooting and hollering. Of course, now that we were falling up to 120 mph the wind was so loud I couldn’t hear anything!

So the title of the post refers to the maximum downward velocity, in this case 120 mph. At this speed the downward pull of gravity is canceled out by the drag of falling through the air, so this is the fastest we went going down. We had about 60 seconds of free fall. Now, it turns out that in tandem jumping the instructor uses a drogue chute to stabilize the two of you. This means our drag was higher than without it, so our terminal velocity was lower. Also, two people falling in a tandem rig would have more weight for the amount of surface area, and their terminal velocity (without the drogue) would be higher. So I don’t really know what a single person’s terminal velocity would be.

Then the instructor pulled the chute and we slowed down. The chute provided much more drag, so our terminal velocity was less. Finally we landed back at the airport. For this the instructor had us dive, then level out just above the ground. We stuck our feet out in front, and hit the ground. Our forward and downward momentum was very low and we skidded for a few feet before stopping.

So Rileysci, how was it?

It was very exciting! Certainly more thrilling than large roller coasters. But I’m kind of old, and I had issues. Isome ear pain when going up in the airplane. Surprisingly, I didn’t notice any pain on the way down, but my body was overwhelmed with other things at the time and didn’t notice. While going down with the chute open I was kind of dizzy, probably from my nervous system being overwhelmed. It’s taken a while for my body to get back to equilibrium (yay homeostasis!). Overall it was something to check off my bucket list, but I won’t do this again.

My son enjoyed it much more and will definitely be doing this again before the summer ends.

#sussexskydiving

Music for Oscilloscopes

First, a story:

Many moons ago, before laser pointers were things you could get at your local convenience store for the cost of a few packs of gum, back when lasers were expensive and cool, my friend got a laser. I’m pretty sure it was discarded by some lab. It was a tube about 5 cm in diameter and about 30 cm long and had a large brick-sized power supply. It was fun to play with, but ultimately it’s just a laser making a red dot on the wall. So Phil, for that was my friend’s name, took a speaker from his stereo, and taped a small mirror to the cone. Then, with the lights out, aimed the laser at the mirror and played music. Suddenly, the music came alive on the ceiling where the laser was being reflected. We called it Philsarium, after Laserium, which had been shown in the 1970s at planetariums.

That’s it for the story. Not much of a moral, I admit, but it was more of a trip down memory-lane. Anyway, the reason I bring it up is this week I saw a certain Smarter Every Day video. This video immediately brought that experience back to mind, except this time the laser is replaced by an oscilloscope. Oh, and instead of using regular music, awesome people in Austria craft music specifically to show different things on the oscilloscope. What normally shows sine waves or square waves (or RS-232 signals that Phil and I had to reverse engineer at one point) now shows everything from Tetris blocks to Tyrannosaurus Rexes.

Like Phil’s laser, the oscilloscope also shows a dot. Normally it shows various waveforms for analysis, but really it just shows voltage visually. By splitting the music’s stereo signal into 2 lines (one for the left speaker, the other for the right) and connecting these 2 voltages to the oscilloscope’s two inputs, the oscilloscope’s dot can be moved around the screen based on what the music does. One input (say the left audio channel) controls the horizontal, and the other input controls the vertical, moving the dot around the screen. By adjusting the voltage for the two channels carefully, you can turn the oscilloscope into an Etch-a-Sketch. And by having the sound change the drawing changes, and you can move and change the image. OK, it may be a long way to go for what is today considered mere music visualization, but doing it on a ‘scope is brilliant.

Those wacky Austrians have made albums of music based on this. The music is constrained by it’s primary audience, the oscilloscope, so it sounds somewhat like raw old school synthesizer music.

There’s a lot of trigonometry involved in this, so the next time a student asks a math teacher “when will we use this”, the answer may be “when you form a band.”