Considering LEGO Robotics

LEGO robots at the St. Louis Science Center.

There was a neat little conference today, organized by LEGO’s Education division. I’ve been trying to figure out a way to include robotics in my math and science classes, but since I haven’t had the time to delve into it, I was wondering if the LEGO Robotics sets would be an easy way to get started. It turns out that they have a lot of lesson plans and curricula available that are geared for kids all the way from elementary to high school, so I’m seriously considering giving it a try.

Pedagogically, there are a lot of good reasons to integrate robotics into our classes, particularly as the cornerstone of a project-based-learning curriculum.

  • The act of building robots increases engagement in learning. Just like assembling Ikea furniture makes people like it better, when students build something the accomplishment means more to them.
  • Working on projects builds grit, because no good project can succeed without some obstacles that need to be overcome. Success comes through perseverance. Good projects build character.
  • The process of building robots provides a sequence of potential “figure it out” moments because of the all steps that go into it, especially when students get ambitious about their projects. And students learn a whole lot more when they discover things on their own.
  • Projects don’t instill the same stress to perform as do tests. Students learn that learning is a process where you use your strengths and supplement your weaknesses to achieve a goal. They learn that their worth is more than the value of an exam.
  • Projects promote creativity, not kill it like a lot of traditional education.

In terms of the curriculum, Physics and Math applications are the most obvious: think about combining electronics and simple machines, and moving robots around the room for geometry. A number of the presenters, Matthew Collier and Don Mugan for example, advocate for using it across the curriculum. Mugan calls it transdisciplinary education, where the engineering project is central to all the subjects (in English class students do research and write reports about their projects).

I’ve always favored this type of learning (Somewhat in the Air is a great example), but one has to watch out to make sure that you’re covering all the required topics for a particular subject. Going into one thing in depth usually means you have to sacrifice, for the moment at least, some width. The more you can get free of the strictures of traditional schooling the better, because then you don’t have to make sure you hit all the topics on the physics curriculum in the seemingly short year that you officially teach physics.

The key rules about implementation that I gleaned from presentations and conversations with teachers who use the LEGO robotics are that:

  • Journaling is essential. Students are going to learn a lot more if they have to plan out what they want to do, and how to do it, in a journal instead of just using trial-and-error playing with the robots.
  • Promote peer-teaching. I advocate peer teaching every chance I get; teaching is the best way to learn something yourself.
  • 2 kids per kit. I heard this over and over again. There are ways of making larger groups work, but none are ideal.

A Plan of Action

So I’m going to try to start with the MINDSTORM educational kit, but this requires getting the standard programming software separately. One alternative would be to go with the retail kit, which is the same price and has the software (although I don’t know if anything else is missing).

I think, however, I’ll try to get the more advanced LabVIEW software that seems to be used usually for the high school projects that use the more sophisticated TETRIX parts but the same microcontroller brick as the MINDSTORM sets. LabVIEW might be a little trickier to learn, but it’s based on the program used by engineers on the job. Middle and high students should be able to handle it. But we’ll see.

Since LabVIEW is more powerful, it should ease the transition when I do upgrade to the TETRIX robots.

The one potential problem that came up, that actually affects both software packages, is that they work great for linear learners, but students with a more random access memory will likely have a harder time.

At any rate, not I have to find a MINDSTORM set to play with. Since I’m cheap I’ll start by asking around the school. Rumor has it that there was once a robotics club, so maybe someone has a set sitting around that I can burrow. We’ll see.

The Visible Universe

Everything depends on your point of view — more or less. Our picture of the universe has changed in the last 60 years as telescope technology has improved. Popsci has a great interactive visualization showing how much more we can see now.

Notice that in this picture, the Earth is at the center of the universe (the Sun is a little way off to the middle lower left). After all, we’re looking at the universe from the Earth, not the other way around.

The universe as it appeared in 1950, compared to what we can see now (2011). Image from Popsci.com

Discovering the Discworld: Where to Start With Terry Pratchett

Rowan Kaiser asserts that Mort‘s the best place to start to discover the wonderful novels of Terry Pratchett.

the Discworld books combine silliness, satire, philosophy, and strong characterization to create a unique, often wonderful tone that’s more than capable of supporting a series with so many installments. But the number of installments can seem overwhelming, especially given that while the books have standalone narratives, they also have consistent sets of characters who develop over the course of the series, leading to an apparently complicated web of a few different, occasionally overlapping series-within-a-series.

–Kaiser (2011): Gateways To Geekery: Terry Pratchett novels in The Onion’s A.V. Club.

My recommendation would be one of her runner-up gateways — either Guards! Guards! or Wyrd Sisters — but she makes good points. Her third runner-up, Small Gods, which is one of the stand-alone novels is one of my favorites, and was my first Pratchett book. And it got me hooked.

Pratchett’s work is intelligent fantasy, in that it’s a lot like the hard science fiction I prefer. It sets up the rules of its universe and then follows them to their logical conclusions, no matter how absurd.

I often wonder how these books would appeal to adolescents since there’s a distinct possibility that much of the quite enjoyable satire would pass over their heads. The Amazing Maurice and his Educated Rodents won the Carnegie Medal for children/young adults, but while it retains Pratchett’s characteristic style and humor, it was written for a younger demographic, unlike most of his other books. I did get one student to read Small Gods, and her response, with a grimace was, “It made me think“.

Beating the Odds: The Sheer Improbability of Being Here

visual.ly posts and hosts some excellent graphics. The one below, calculates the nearly infinitesimal probability of just being born. There’s hardly a better argument for appreciating life.

It’s also a good example of working with probabilities [and] exponents. Very large exponents.

by visually via

The Case Against the Electoral College

C.G.P Grey makes the case against the Electoral College in video form. He starts with how the Electoral College Works and continues with a well reasoned polemic against it: he’s big into democracy — one person, one vote.

How the Electoral College Works

The Trouble with the Electoral College

Making a Non-Stick Frying Pan the Old Fashioned Way: Creating Polymers at Home

"Seasoning" a cast iron frying pan creates a non-stick coating. (Image by Evan-Amos via Wikipedia).

Back in the day, if you wanted a non-stick cooking skillet, your best option was to do it yourself by seasoning a cast metal pan. Sheryl Canter has an excellent post describing the science behind the “seasoning” process. The key is to bake on a little bit of oil to create a strong cross-linked polymer surface. This is a nice tie into our discussion of polymers and polymerization in the middle school science class; although I’m not sure how many of my students have actually seen a cast iron pan, or even know what cast iron is.

Normal polymers are long molecules made up of smaller molecules linked together, much like a paperclip chain.
Cross-linked polymers are created when the long chained polymers are linked together by cross-links. It makes for a much sturdier molecule.

To season, you coat the pan with a thin layer of oil and bake it for a while (without anything in it). Baking releases free radicals from the metal that react with the oil to create a cross-linked polymer that’s really hard to break down or wear out, and prevent food from sticking to the pan. Different, cross linked polymers are used in car tires for their durability, but probably not for their lack of stickiness.

Apparently, linseed oil is the best seasoning agent, but it might be a bit hard to find.

Most non-stick, artificial surfaces, are also made of polymers of hydrocarbons, silicon oxides and other interesting chemicals.

Making a cross-linked polymer with borax and polyvinyl alcohol.

In the lab, you can make your own cross-linked polymer “slime” by adding a solution of borax (sodium tetraborate) to a solution of polyvinyl alcohol (1:1 ratio of concentrations) (Practical Chemistry, 2008).

The result is a satisfying goo.

Cross-linked polymer "slime".

Media Profanity and Aggression

This research shows that profanity is not harmless. Children exposed to profanity in the media think that such language is ‘normal,’ which may reduce their inhibitions about using profanity themselves. And children who use profanity are more likely to aggress against others.
–Brad Bushman (2011) in a Brigham Young University Press Release.

Exposure to profanity in videogames and on TV appears to affect how teens view and use profanity, and makes them more aggressive. These are the key results of a paper by Sarah Coyne (Coyne et al., 2011). The full article is available online, but is summarized here.

While the first part, at least, of this result might seem obvious — that seeing profanity desensitizes, familiarizes, and leads to increased use — it’s nice to have some scientific corroboration.

The more disturbing result, perhaps, is the link between profanity and aggression. It’s a moderate effect, but the link appears similar to the connection between war games and aggression.

Profanity is kind of like a stepping stone. You don’t go to a movie, hear a bad word, and then go shoot somebody. But when youth both hear and then try profanity out for themselves it can start a downward slide toward more aggressive behavior.
— Sarah Coyne (2011) in a Brigham Young University Press Release.

Sling: A VPython Model Demonstrating Centripetal Force and Conservation of Angular Momentum

Animation captured from the sling.py Vpython model. The yellow arrow shows the centripetal force. The white arrow shows the velocity.

Sitting in a car that’s going around a sharp bend, its easy to feel like there’s a force pushing you against the side of the car. It’s called the centrifugal force, and while it’s real to you as you rotate with the car, if you look at things from the outside (from a frame of reference that’s not rotating) there’s really no force pushing you outward. The only force is the one keeping you in the car; the force of the side of the car on you. This is the centripetal force. Given all the potential for confusion, I created this little VPython model that mimics a sling.

Centripetal Force

In the model, you launch a ball and it goes off in a straight line. That’s inertia. An object will move in a straight line unless there’s some other force acting on it. When the ball hits the string, it catches and the string starts to pull on the ball, taking it away from its straight line trajectory. The force that pulls the ball away from its original straight path is the centripetal force.

Image from Stern (2004): (23a) Frames of Reference: The Centrifugal Force

Conservation of Angular Momentum

The ball rotating on the sling has an angular momentum (L) that’s equal to the velocity (v) times its mass (m) times its radius (r) away from the center.

L = mvr            , angular momentum

Now, angular momentum is conserved, which means that if you shorten the string, reducing the radius, something else must increase to compensate. Since the mass can’t change, the velocity has to, and the ball speeds up.

The ball on the string with the shorter radius has the higher velocity (moves faster). It also has a higher centripetal force. The ball for shortening the radius is not shown in this figure.

I’ve put in a little ball at the end of the string that you can pull on to shorten the radius.

Tangential Velocity

Once the ball is attached to the string, the centripetal force will keep it moving in a circle. If you release the ball then it will fly off in a straight line in whatever direction it was going when you released it. With no forces acting on the ball, inertia says the ball will move in a straight line.

The ball, when released from the string, flies off in a tangent.

To better illustrate the ball’s motion off a tangent, I put in a target to aim for. It’s off the screen for the normal model view, but if you rotate the scene to look due north you’ll see it.