Tuesday, October 6, 2009

LEGO Education 9797 Parts Poster

One of our engineers made up these fine posters (PDF, 3 pages, 3.8 MB) that give names for all of the parts in the LEGO Education 9797 NXT set. They're formatted for 8.5 x 11" paper, but can be scaled up - we printed up poster-sized versions and they look really nice. (The image to the right is just a thumbnail. Click the link to download the PDF.)

Monday, October 5, 2009

The Grinding of the Gears

We spent the last two weeks working on gears - showing the students how gears work, that they speed up or slow down, and that they let you trade off speed for torque (which we just called "power" - apologies to hard science majors). We then tried to get them to add gearing to NXT motors. As with the previous activities, we tried to let them figure out how to do it. I don't like to use the word "disaster", but the students were pretty frustrated by the end of class. We decided to extend the activity to the next week, giving them direct instruction about how to add gears, and preserving the cars that had been constructed.

I had thought, for many years, that adding gears to the output of NXT motors would be a big hassle. It turns out to be quite easy - all you need is to use a "lift arm" (bent beam) attached so that it gives you holes in horizontal or vertical alignment with the motor axle. The very simple framework pictured here lets you add three different pairs of gear sizes: 24:24, 8:40, or 12:36 (thick "knob" gears). Of course, the latter two can be applied to either reduce or increase speed.

So, we told the students to add the 24:24 gears to the motor, as pictured above, and measure how far the car goes in 5 seconds and see how well it climbs up a 30-degree ramp. (We have 350 cm (12 foot) tape measures for each group and are having them do all measurements in metric.) We then asked them to replace the gears with the 8:40 gears and repeat the experiments. They could choose whether to have a "race car" or "tow truck". I had expected that this would be easy for them - just pop the wheels and gears off, put on the other gears, and put the wheels back on. Nevertheless, most of them still had a lot of trouble. A few of them tried to put the wheels on the motor output, ignoring the gear. I'm not reporting this to chastise them - I think that they just weren't quite ready for this activity. After all, most of them had never seen a gear before this, much less tried to build anything with them.

After the last gears class, we had a meeting with the teachers to figure out what we could learn from the experience. We realized several things:
  • Most of the students are not yet comfortable building with the parts. We tried to deal with this by giving them detailed instructions for building things.
  • In trying to make it easy for the students to experiment with the gears, we'd reduced the activity to direct instruction - "build this, add that, do it this way" etc. They didn't have any opportunity to be creative, which is what had made the first classes so much fun and energizing.
  • There had been no chance for them to present their work - another part that they'd enjoyed - since they were all building the same thing.
  • Although they'd definitely learned about gears, it just wasn't fun - and we believe that there's no reason that these activities can't be fun.
We resolved that the next activity would focus entirely on building, with as much opportunity for creative design as possible. They're going to build bridges to help a family of batteries get across a river. More on that later.

There were some good things that we did which engaged them.
  • They liked measuring how far their cars would go. We collected the distance measurements and they showed a great distribution. If we'd had more time, those numbers would have been great fodder for discussing why apparently identical experiments give different results.
  • We used a ramp to demonstrate the speed vs. power trade-off. They all wanted to try their cars on it. Few of them could believe that their race car wouldn't go up the ramp even the slightest bit, no matter how many other race cars they saw stall.

Sunday, September 27, 2009

The NXT Brick - Unplugged

The NXT 2.0 software includes new firmware (see previous post) that lets you create simple programs directly on your NXT brick - no computer required. I've prepared an exhaustive tutorial for your enjoyment.

Monday, September 21, 2009

Hardware, Software, and Firmware

Apologies if this post sounds like an advertisement for LEGO products...

To get set up for the LEGO Engineering program, the school bought the LEGO Education NXT kits - the standard 9797 set. We also bought a site license for the NXT Software 2.0, which (new in 2.0) includes "data logging" capabilities. That means that you can take measurements (using any of the sensors) over a period of time and record the data. You can then graph the data - either on the NXT or on a computer. I'm really looking forward to using these capabilities. Note that there's no difference in the NXT brick - it's just the software.

Firmware Version 1.28
With the NXT 2.0 software comes a firmware update, to version 1.26. But... don't install it. I heard from one of the attendees at our LEGO Engineering Conference that his NXT sometimes froze when doing line-following. The good news is that there's a firmware update (1.28) which he said fixed the problem. I highly recommend it. It has a very, very cool feature: you can do simple programming directly on the NXT brick - no computer required. I'll try to make a post about that feature.

Based on one person's experience, the 1.28 firmware seems to be compatible with the 1.0 NXT software - which is great! However, if you decide to try it, make sure that you have the older 1.05 firmware handy in case you need to revert - just in case.

One annoyance is that the firmware comes in a ".rar" file, an archive format like ".zip" or ".sit". I had never heard of it, which is saying something. On Windows, I'm told that WinZip, which you may already have, can unpack the file. If you don't have WinZip, the free utility 7-Zip will do it. On the Macintosh, a program called The Unarchiver will do the trick.

Charging Multiple NXT Bricks
I lied. The school didn't buy the standard 9797 kits. Those come with the rechargable battery (good) and a wall-wart style battery charger (bad). I hate wall warts. I especially hate the thought of 16 of them plugged into 5 or 6 power strips, plugged into another power strip. So, I had the school buy the W991501 8-Pack plus light sensor - you get a second light sensor and no battery charger.

So, how do we charge the batteries? Long ago, I started out as an electrical engineer and I still like to tinker. I built 3 "multi-chargers" that can each charge 5 NXT bricks. They take up way less space, have longer cords, and less wire tangling.

Friday, September 18, 2009

Motors are hard to attach, let's play with the wheels!

Today was the first day of the second week, which was "build a sturdy car". We showed them the sample car from the curriculum, which was - intentionally - pretty lame, but the net result was that most of the kids just completely froze on the problem. After all, look at them:

Most of the obvious ways have bits getting in the way or end up with the wheels pointing the wrong direction. This was my moment of quiet panic. So, we showed them the basic double-joiner elements:

and they got the idea that you could use those to directly attach the motors to the sides of the NXT brick. So, most of the cars were wide, like this:

But there were several interesting designs:

Nevertheless, too many kids didn't know where to start and endured a lot of frustration. We still want them to wrestle with the design process, but some of them clearly needed some hints. So, I found this great resource from the LEGO Engineering site: Constructopedia 2.1 | Ways to Attach NXT Motors (PDF, 29 pages) It shows 8 different ways with detailed building instructions. Since we don't want to take away all of the "fun", I think that we might just provide copies of the overview picture for each design - to be used as needed. (Oh, and even if we give them a solution for motor attachment, they still have to figure out the "front" wheels.)

End-of-week update:
Providing the motor attachment hints really helped. Most of them (that needed the help) were able to get by with just seeing the overview picture, not the detailed building instructions. Here are some of the other cars:

Wednesday, September 16, 2009

Parents' Night in the Lego Engineering Classroom

You remember parents' night at school, right? Parents get to go to your classrooms, sit in your desks, listen to your teacher talk about what you'll be doing all year. The Lego Engineering classroom on Wednesday night was a bit different....

Children who had temporarily escaped their parents were clustered around desks taking apart and putting together parts of the partially-assembled cars from Week 2. Parents would occasionally walk in looking lost (as we were not giving any formal presentations...too boring), and given that I speak Spanish and many of the children come from Spanish-speaking households, I would rein them in by asking them if their kids had told them about the class. The lost look would disappear, and they would tell me how much their children had been talking about this class and how the older siblings were jealous that it hadn't been offered when they were in 3rd or 4th grades.

I told them some of the basic principles that their children would be learning about, e.g., how to solve problems by trying things out rather than reading text books and answering questions. One mother was fascinated because her child has been having trouble paying attention in school, and for the first time has become fully engaged in a class (and of course is begging for an NXT kit of his own). She sees the connection between this class and the basic skills he needs to work on, like reading: if he wants to pursue Lego Engineering as a hobby, in the absence of a teacher or volunteer, he'll need to read instructions, find information on the web about how others have solved problems, etc.). Another family had two younger daughters not yet old enough for the class, and simply wanted to find out what all the excitement was about. They were genuinely grateful to the Google volunteers for their time and effort, and recognized the value of exposing children to alternate forms of learning that they may not have access to at home.

Saturday, September 12, 2009

More Observations regarding STOMP

[Originally posted by Joe]
  • Kids love wheels. Most of the kids started on the chair exercise by figuring out how to attach wheels to a flat surface. I'm not sure why. I tried to point out that the goal of the project was to build a chair, and that the wheels could come later.
  • I also note that design sessions at Google often start with the wheels, even though the goal is a chair!
  • The handouts we had for the initial activity (building an arch) were hard to read. The graphics were so dark that a key part was nearly invisible.
  • We didn't spend enough time teaching kids how to put together the "new style" Lego parts. Most of them tried to attach parts the old way (with stud and hole) rather than the new way (beam and connector).
  • Random assignment of kids to teams mostly worked, but we had one team that lagged. One of the boys had difficulty understanding the assignment, and some problems with manual dexterity. The other boy was either bored or unmotivated, and didn't spend much time doing anything other than fooling with parts and singing to himself.
  • My experience justified my prior belief that we don't pay teachers even half of what they're worth.

Wednesday, September 9, 2009

Our first day in the classroom

The first activity was "A Chair for Mr. Bear", where the kids had to build a chair out of LEGO elements that would hold a small stuffed bear and meet a couple of requirements: sturdy enough to survive a drop to the floor and stable enough to not fall over if you gave it a little shove. The main purpose is to introduce the kids to the parts they'll be using and to teach them a bit about how to build strong structures. (Remember the bridge that didn't fall down?)

A little bit about the classroom...

We have a separate group of volunteers assigned to each of the three fifth-grade classes. The classes have about 30 kids each, with the kids working in pairs. The LEGO Engineering sessions are 90 minutes long, right at the end of the school day. Working in pairs seems to be universally regarded as the right choice for this activity:
  • There's no way to have 30 LEGO kits and enough room to work.
  • Teamwork skills are essential all through life - we may as well start now.
  • Three-person groups do not work at all - one kid will always be sidelined.
Note that this is not a special choice program: all of the kids in the class participate. Pairs are randomly assigned by drawing labeled craft sticks (a.k.a., tongue depressors) out of a "sorting hat" at the beginning of each session.

Back to building chairs...

One thing that I enjoyed pointing out is that the first two engineering steps (identify the need; research the need) were being done for them: We're telling them that the bears have sore feet and that the solution is to build chairs for them. I also point out that a good engineer who did proper research would probably have come to the conclusion that several sacks of leaves might be a better solution.

We showed the kids several deliberately-flawed chairs and let them go at it. On the first day, we realized that most of the kids had no idea what the different LEGO Technic parts did or how they could connect together. On later days, we had them build some simple structures (PDF, 3 pages) as a warm-up exercise. I'm not really sure that that helped, because we got a lot more "successful" chairs on that first day. Go figure.

Once a couple of pairs had chairs built, we had them come up and present their designs. They were not expecting this! However, they were all excited to present their (emphasis on ownership, here) chairs and describe the cool features. They really liked having us take pictures of their chairs. I built a light tent to take the pictures, and am thrilled at how well it worked.

Here are a few bear chairs.

Note: variations in bear-like characteristics should be expected and are a natural consequence of the bears' origins.

What do engineers do?

The first week's activity starts with a gentle introduction to the engineering process, which the Tufts curriculum describes as consisting of 8 parts:
  1. Identify the Need/Problem
  2. Research the Need/Problem
  3. Develop Possible Solution(s)
  4. Select the Best Possible Solution(s)
  5. Construct a Prototype
  6. Test and Evaluate the Solution(s)
  7. Communicate the Solution(s)
  8. Redesign
Current events provided us with an excellent illustration of an engineer's work: The weekend before, a truck carrying a large backhoe was 6 inches (15 cm) higher than the Mathilda Ave. overpass at Highway 101. Large chunks of concrete were ripped out of the bridge (fortunately, not causing any injuries) causing the bridge to be closed for a few days while they figured out how bad the damage was. This gave us some great talking points about engineering:
  • Why didn't the bridge fall down? [Engineers designed it to be strong against heavy loads, earthquakes, and damage like this.]
  • Who did they call in to see whether the bridge could safely carry traffic and be re-opened? [Engineers, of course.]

Tuesday, September 8, 2009

Introductory message...

Google engineers teaching fifth-grader students using LEGO toys?

Ever wonder what Google engineers do for their 20% projects? Well, this one isn't typical...

Back in December of 2008, we invited some folks from Tufts University's Center for Engineering Education and Outreach (CEEO) to talk about "LEGO Engineering, from Kindergarten to Graduate School" (video). They described how LEGO building toys - especially the NXT - can be used to enhance science, technology, engineering and math (STEM) education at all levels. Not only that, but Tufts have a program which they call STOMP (yes, it's an acronym) that brings LEGO Engineering into the classroom. They provide training, curriculum, and a community.

I've wanted to find some way to bring these sorts of educational tools to under-represented communities. I fit in well at Google - we are seriously interested in increasing diversity in engineering-related fields - we need our future engineers to reflect the diversity of the people using our products. Interested? Totally!

The project is described in greater detail here, but the short summary is that small teams of Googlers will spend 90 minutes, once a week, teaching LEGO Engineering at Bishop Elementary School in Sunnyvale (near Highway 101 and Mathilda). We're using the curriculum provided by Tufts, modified to fit our experiences.

We started off, on August 24, by holding a LEGO Engineering Conference to get the teachers and volunteers familiar with the program. The next step is to for the volunteers to actually start teaching in the classroom. That will be another blog post. And another. And another...