Archive | June, 2011

LEGO WeDo Vehicle Challenge: Using WeDo kits with older students

20 Jun

The LEGO WeDo kit is designed and marketed for early elementary children. It’s so basic that even a first grader can use it, but be careful not to write this kit off as a “just-for-the-little-kids” kit too quickly.

This year, one of my favorite mini-lessons with the 7-9th grade students in the after school STEM club was this “WeDo Vehicle Challenge”:

Design a WeDo vehicle that has either 2, 3, or 4 wheels. Use only the pieces in the Wedo kit. The vehicle does not need to have steering, but it must be able to drive forward and in reverse. Innovation is encouraged. You have two class periods (1 hour each). We’ll present at the end of the second.

The kids usually take a look at the WeDo kit and presume the challenge will not be much of a challenge. Once the students get started, it isn’t long at all before they realize what makes it challenging; there is only one motor, the motor is fairly heavy relative to the parts, and that the axle sticks straight out of the center of the motor. Hmmm….

I’m guessing the challenge is probably easier for students that have prior experience working with LEGO kits and robotics; I’m not sure. (Let me know if you try it.) All my students were new to working with the NXT kits when I tried the WeDo lesson. I wanted to see how they worked when asked to think out of the box and to be creative. Following a blueprint is great for developing spatial skills and following instructions, but it doesn’t necessarily foster innovative thinking.  I found that forcing the students to work with the limited parts of the WeDo kit encouraged them to be persistent, to attempt multiple solutions, to redesign and improve, and to work together.

I’m curious if other teachers and after-school educators have tried using the WeDo kits with older students? Let me know!

Here are a few examples of our WeDo vehicle designs if you are curious… (The kids filmed the clips.)

Taking Damien Kee’s NXT “Mexican Wave Activity” for a Test Drive

16 Jun

In my last post about the Tufts LEGO Engineering Symposium, I mentioned Damien Kee‘s  presentation and included an embedded  video of his NXT “Mexican Wave” activity.

Yesterday morning, I tried the activity with a group of 21 fifth graders that had never worked with robotics before and it was a blast! It was the perfect activity for introducing the kids to the NXT robots and the NXT-G software.

We met from 9:30-12:15 and took a 15 minute snack break, so all told, we had about 2.5 hours to try to meet the following three objectives:

1) Work collaboratively in small groups to program the NXT Domabot to move from one specified location to another. Time permitting, write a program to turn the robot around and have it return to it’s starting position.

2) Gain a basic understanding of what sensors and thresholds are and find out how they apply to today’s activity.

3)Work collaboratively as a class to program all five NXT Domabots to do a wave and at least one additional choreographed movement.

Students collaborated well and worked hard and met all three objectives by lunch!

After reviewing the objectives, we warmed up with a five minute activity called “Computer Says”. (The activity is similar to Simon Says. I am the computer; students are the robots. Robots should only follow programs that start with “Computer says”) Students made three lines and faced me.

For Round 1, I said, “First we’ll learn use a motor block to run simple programs. Let’s try a few.” I then led them through a few simple commands,  “Computer says take one step forward.”  “Computer says take one step back”.

In Round 2, I said, “Next we’ll learn to use a “wait-for-sensor block and write slightly more complex programs.” I then gave a few commands like these: “Computer says wait until you hear me clap, then take one step forward. Computer says, wait until I shout loudly and then jump”

And finally for Round 3, I said, “For our third objective, we will have to collaborate to write a series of programs to get our robots to work together to create a movement wave. Let’s try to run three programs at once and see what happens. Computer says, Line 1 robots, wait until I clap then put both hands in the air and back down again. Line 2 robots, wait until I clap, then wait one second, then put both hands in the air and back down again.  Line 3 robots, wait until I clap, then wait two seconds, then then put both hands in the air and back down again.” I clapped my hands and watched as the students did a perfect mini-Mexican-wave!

The whole activity took less than 5-minutes, but it helped to build a context for what came next. Being able to refer back to the warm-up came in especially handy when we started thinking about how to program the robots to do a wave.

After our warm-up, students then learned to move their robots using a single motor block. As recommended by Damien in his presentation, I placed two lines of tape on the floor at a random distance from each other and then students worked to program their robots to start with wheels on the first line and stop with wheels on the second line. They set to work trying different motor on durations and very quickly developed an appreciation for the decimal point! If 5 rotations were too many, they tried 4, then 4.5, 4.6, 4.7…

They began to see that trial and error and persistence were important for solving this problem, and they experienced the intrinsic joy that came along with finding an exact solution to a problem.

Soon all groups had mastered the line-to-line challenge and were on to trying to figure out how to turn the robot around and bring it home. Despite my having mentioned that changing the “degree” parameter of the motor block to 180° would not turn their robot around, all the groups tried that strategy first, which led to a series of great teachable moments surrounding what “rotation” meant in the motor block. After some experimentation with the remaining parameters in the motor block, groups soon started to catch on that the steering parameter in combination with the duration setting was the ticket to that 180° turn. At least two of the five groups got the turn close to an exact 180° turn, and the remaining groups were well on their way before I cut them off and moved on to objective 2.

Once the kids had a general sense of how to move their robots and turn them, we regrouped and I introduced them to the sound sensor and to the threshold parameter.

As I usually do when explaining threshold to kids, I said, “I bet you already know what threshold means. Let me show you. Listen to my voice and when I reach your threshold between soft and loud, clap.”

I then talk very quietly and get progressively louder until they clap. I repeat and set the threshold for “really loud”. I do a few more examples of simple thresholds they understand. For example, their threshold for drinking hot liquids. I quickly made the correlation to the threshold parameter on the  sensor block. Students seemed confident they understood the wait-for-sound block and so we moved directly on to discuss how to create a wave.

To plan the wave, we created a chart on the wall that sketched what each group needed to do and then parted. We met back up about five minutes later.

On the kids’ first try, the robots took off and executed a perfect little wave. Wow! We had thirty minutes left to add a choreographed movement of our choice. We lined up 5 students to represent the five robots and planned our dance move. Groups ran off in all directions to program. Shortly after we met back up, pushed run, waited for the signal and yelled “Go” What came next was…

Terrible. Our little robots were all over the place. And so we began to learn about collaborative trouble-shooting. We came back to the line over and over again, each time it got better, but something wouldn’t be quite right.

With one minute left and groups scrambling to download their last attempts, I called them back to the line. The room was quiet. Thumbs went up to signal all programs were running. Their classroom teacher quietly counted “1-2-3” and then the kids yelled “Go!” one last time. You can see for yourself the fruits of their efforts in our video. The simple sequence of movements won’t blow your mind… but the kids’ cheers and screams of enthusiasm may brighten your day. 

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