Tag: st. louis

Lego Mindstorms

I’ve been curious about the Lego Mindstorms robotic systems for a while now, and I had my first chance to try them at the St. Louis Science Center.

The kits come with a micro-controller, a few motors and some sensors. While there are quite a number of ways of assembling these to make robots, the ones at the science center were pre-built except that you could just plug in a bulldozer or sweeper attachment (and a head which was purely decorative). This limited the degrees of freedom to three, which made it easier to program something useful in the hour we had with the robots.

The programming is very basic. There are two sets of instructions, one to control the movement of the robot in general, and one to control its response when the sensor detected a change in the environment. The objective of the science center’s game was to clear off a set of objects from a white rectangle within five minutes.

You could tell the robot to move forward, back or rotate while it’s on the board and to activate its sweeper or shovel. So a full program could have just five elements; general: lower shovel –> move forward –> rotate; sensor: move backward –> rotate. With these strict limitations, the programming interface is also very simple; you plug in blocks with each instruction in the series for either the general movement or the sensor reaction. With all this simplification, I’m not sure just how much the students learned about programming from our short session.

The full kit from Lego offers more freedom to design robots and thus more flexibility with the programming interface so with a little thought it could be easily integrated into the curriculum. At about $300 each the system is a bit pricy, we’d probably need to get one kit for each small group of 3-4 kids. They would probably be worth it however if we used them more than just once.

I’ve been playing with the Basic Stamp micro-controller for a while, and while it offers almost infinite flexibility, making it more useful for practical applications, it does not provide the immediate gratification of the robots, and the ease of assembly to make it the better tool for introducing robotics to middle schoolers. I still, however, tend to favor practical applications, so perhaps I can persuade a student to do an advanced project to build an automatic window for the greenhouse.

The session at the Science Center was worthwhile. All of the students seemed to enjoy it. It provided a nice integration of the mechanics and electronics we’ve been learning about all year, and a glimpse of where technology is taking us in the future.

Anheuser-Busch and the industrial revolution

Fermentation vats.

Why take a group of middle schoolers on a tour of the Anheuser-Busch factory? After all, no one will be trying any samples and the main point of the museum and the tour itself is to make people feel good about the company and buy more of its products. Which would be beer.

Rail track leading into the brewery.

The answer is that the history of the company ties directly into the history of the industrial revolution in the U.S.. Its large scale industrial process was made possible by the serendipitous German immigration into St. Louis in the late 1800’s. Just then the expansion of grain farming in the mid-west and the railroads could supply the raw materials for beer on a massive scale. New assembly lines and automation could efficiently process these inputs, resulting in large scale production. Successes bred new inventions, with the company retaining the services of Rudolph Diesel to introduce his engine to the U.S..

Assembly line producing hundreds of bottles a minute with only five workers.

The survival of the company during prohibition (1920-1933) was another point of interest. Anheuser-Busch survived by diversifying from its core business, making non-alcoholic drinks and selling baker’s yeast among other things. At the end of prohibition, Anheuser-Busch was the only large brewer left in the city St. Louis.

Barley.

We also saw a bit of chemistry during the tour. The breakdown of complex starches into sugars as part of the fermentation process is a basic example of organic chemistry in action (polymers –> monomers). Light beer, for example, is kept in the tanks longer so that more of the starches are broken down into simple sugars. There were even a couple of big models of barley grains and hops buds showing their parts, that tie in to our life-science lessons next year.

First encounter with the barrage of advertising.

Even the surfeit of advertising could be used to advantage; the first thing inside the door of the museum is a television playing Anheuser-Busch’s most successful commercials. We’ve been discussing propaganda all year, so the students were somewhat inoculated to the barrage of feel-good messages, and we specifically discussed this in our post-tour group meeting.

Our tour guides were great. Informative, friendly and willing to answer questions, I particularly appreciated that they joined us in our group discussion after the tour and answered the questions that came up as best they could.

This tour exceeded my expectations.

Scrap metal playground

The St. Louis City Museum is an excellent place for the kinestetic. They assembled scrap metal from all around the city, including coils of metal, wire fencing, steel-plate slides and airplane fuselages, and gave it to artists to produce an exceptional, innovative playground.

Wire tubes extended across the air, two-three-four stories high, barely wide enough to crawl through. If you’re claustrophobic and afraid of heights you would think it would be a nightmare, but the wire mesh is sturdy enough that you feel secure, while being open enough to so you don’t feel closed in.

There’s other stuff inside the museum, the staff says it’s always under construction, including a warehouse of gargoyles and building facing saved from demolition, however it’s the outside that’s most remarkable.

Glassworks

Molten glass, upwards of 2000 degrees, cools slowly, quickly, slow enough to pull, twist, fast enough to feel the brittleness between metal tweezers in seconds. Runny to viscous as it cools. Change of state — freezing — feel it in the glass.

Tweezers and jacks keep hot glass at a distance. Third class levers require balance and firmness to control their mechanical advantage.

Glass, silica, SiO2. Quartz crystals, ordered array of molecules. Glass, no organization, amorphous.

Furnaces blast hot, you can see the yellow-orange color, you can feel the hard infra-red light, thermal energy. IR – long wave – less energetic. When extra heat is needed, the blue/ultra-violet flame of propane (mixed with oxygen). UV – short wave – high energy – hard on the eyes though you can’t see it.

Combustion needs three things, heat, fuel and oxygen. Propane, C3H8, not methane, CH4 – the greater energy density. Propane, C3H8, not butane, C4H10 – is a gas not a liquid. To burn real hot needs extra oxygen.

Propane torch.

Conservation is a challenge. Furnaces –> heat –> lots of energy –> bad. Natural light, big doors, lots of windows. Recycle glass (at least the clear glass). No need for heat in the winter. Drink lots of water in the summer.

3rd Degree Glass Factory, make your own paperweights. About 12 minutes per person. Excellent way to spend a morning. Really cool faucets and water basins in the bathroom.