One of my favorite things to do is visit with school kids who are interested in engineering or science. However, realistically, there is a limit to what you can do in a single class that might last 30 to 90 minutes. I recently had the chance to work with a former colleague, a schoolteacher, and The Teaching Channel to create an engineering unit for classroom use that lasts two weeks.
This new unit focuses on an egg drop. That’s not an original idea, but we did add an interesting twist: the project develops a “space capsule” to protect the egg, but also an electromagnetic drop system to test the capsules. The drop system allows for a consistent test with the egg capsule releasing cleanly from a fixed height. So in addition to the classic egg drop capsule, the kids have to build an electromagnet, a safe switching circuit, and a test structure. Better still, teams of kids can do different parts and integrate them into a final product, closely mimicking how real engineering projects work.
There are a few reasons for the complexity. First, given ten class sessions, you can do a lot more than you can in a single day. Second, I always think it is good if you can find exercises that will appeal to lots of different interests. In the past, I’ve used robots and 3D printers for that reason. Some students will be interested in the electronics, others in the mechanics, and still others will be interested in the programming. Some kids will engage in 3D modeling (robot simulation or 3D objects). The point is there is something for everyone.
Drop Control can be a Class in Itself
Not only does this diversity help engage students, but it also offers many teaching opportunities. You can easily use the system as a springboard to discuss different types of force and energy (electrical, electromagnetic, gravity), for example. The switching circuit can be a simple SPST switch, or it could be a complex system with a safe switch and even indicator lights. It doesn’t have to be very complex. My prototype used a few bucks worth of switches from Home Depot (see left).
In fact, although you can make things as complex (and as expensive) as you like, it doesn’t have to cost much at all. A budget-conscious school could use zip lock bags as the capsules, tin can lids for magnetic attachment, homemade electromagnets, and forego the switches for a direct wire to the battery. Or, you could let your Arduino class create a complicated fire control system.
To change the emphasis of the exercise, you can tune various parts of the project. For example, you can assign different pieces to different classes or groups and have one group that integrates the final product. The teacher can provide complete parts to deemphasize those portions. For example, a ready-made test stand or an electromagnet can make the project shorter or easier.
Learning About Design Decisions
As you can tell in the video, Tony Castilleja and I have a good time working with the kids. As they design the parts of the system, I like to discuss design trades: the balance of cost, weight, power consumption, and other factors to decide what design choice is “best.” They never fail to surprise me with their creative solutions. We’ve seen cushions, parachutes, and even seat belts. As designers, we take it for granted that “best” doesn’t necessarily mean anything without context. What’s the best kind of truck? The answer is different if you are hauling gasoline instead of chickens. Exercises like this one help future fledgling engineers get that same type of insight.
It also can improve your communication skills. One thing we tried to get the kids to do was to produce drawings before they built things. My old drafting teacher (Mr. Stewart) always emphasized how you had to have enough dimensions on a drawing that someone could build the thing. If you had too many dimensions, he might mark off a few points. But if you didn’t have enough, you were getting an F. It surprised us, however, when some of the kids drew their boxes, measured the lines on the paper with a ruler, and dutifully wrote down the measurement of the line on the page! It surprised us, but it shouldn’t have. It was an entirely understandable interpretation of our instructions unless you had the background that we all have.
The Teaching Channel does an excellent job providing course material (under creative commons) like this to schools. If you browse their video section, you’ll see they have many similar modules. The real unsung heroes, though, are the teachers like Destiny Woodbury (seen below, on the right). The amount of extra time they put in to make sure these future engineers get hands on experience is nothing short of humbling.
Last year, I posted about a very abbreviated version of the egg drop that I do when I just have an hour with the kids. Although it isn’t as involved, they still have fun, and I can still work into my design trade talk. In that case, their selection of materials drives their weight and cost but still has to be effective. With either project, you can even put the A in STEM, and have students decorate the eggs, the capsules, and the controller boxes.
The video below is kind of an overview of what the unit is about. You have to visit the TeachingChannel.org Web site to download the supporting materials, if you want the actual materials and notes.
I’d encourage anyone with enough interest in technology to read Hackaday to get involved either with outfits like the Teaching Channel or just with your local schools and teachers. The cost to you is small, and the rewards can be very high. To quote from the video, one of the students told a teacher in another class “This is the best day of my life! I’m going to be an engineer!” You can’t put a price on that.
Thanks to Tony Castilleja, Destiny Woodbury, and the rest of the team who worked on this unit (especially last year’s class at the KIPP Liberation middle school).