Wednesday, March 30, 2011

Keep it Simple

I'm thankful for lots of things in this world. Some of those things are General Tso's chicken, hugs from my kids, and simple machines.

Simple machines doesn't mean machines that don't know much. It means tools that provide mechanical advantage, or increase the amount of work someone is able to do. The six simple machines are the pulley, wheel and axle, lever, wedge, screw and inclined plane.

Any of these six can be combined to make more complicated machines, like.... marshmallow launchers.

I have to admit that as a teacher my lesson plans often include elements to make me laugh, but this time I think it was the students who got the laugh.

This week myself, two bags of large marshmallows and twenty-some students covered the basics of simple machines and used at least one simple machine to make three launchers: high-flying, far-flying, and precise flying to a target.

It was highly amusing to see four teams of students working furiously with styrofoam cups, lego blocks, rubber bands, foam plates, bamboo skewers, a yardstick, paper and tape. Launchers went on a table and marshmallows went in the launcher so that no part of a student touched the mini-astronaut before it flew.

There were a number of lever-type launchers with fulcrums, some "wheel and axle" devices with the skewer poked through a plate and a notable, alarming bow and arrow. To be fair, the only simple machine really in the bow and arrow was a foam plate wheel on the bottom, but they did cover themselves. The arrow group stuck a marshmallow on a skewer, ran the skewer through a hole in the yardstick, used rubber bands for tension, and swish - I've never seen a marshmallow move so fast.

I have to disclaim here that my husband was rightfully upset with me since I had as the target for precise launchers my face, and more specifically my mouth. In my defense I was picturing soft arcs of delicious marshmallows, not speedy dangerous marshmallows, but still - don't shoot sharp things at anyone's face, not even if the sharp things are tipped with marshmallows.

The goals of this exercise were to teach a STEM concept (simple machines), foster creativity, practice the design cycle AGAIN, and have students own these ideas by doing and making. I'd say it went well. My only change would be to have someone else hold the bag of marshmallows. I think I ate about twenty of them.

Wednesday, March 16, 2011

Tsunamis, Engineering and Compassion

Scale model tsunami zone

I felt conflicted over this week's lesson on engineering structures for tsunami survival using a scale model. I didn't want students to laugh over or trivialize the enormous trauma our brothers and sisters in Japan are undergoing. I did want to give them a better sense of a giant wave's size, scope and destructive power while teaching about tsunamis being a natural (unpreventable) disaster. Not a single person should think that anyone in Japan bears fault for the earthquake or tsunami. I want to help in some way by contacting a Japanese homeschooling group similar to ours here to find out what we can do. I'll update everyone as that effort comes together.

The facts:
  • Tsunamis travel faster than the beach waves we bob in. Most beach waves are created by wind traveling over the ocean for long distances. Their speed must be less than the speed of the wind. Tsunamis are created by earth movement in the deep sea and are not limited by wind. They can travel up to 500 mph.
  • Tsunamis are much higher than beach waves. Because of how shorelines are shaped, a two-foot shift in deep seabed can translate into a thirty foot (or higher) breaking tsunami wave at the coast.
  • Engineers can improve building tsunami survival odds by materials design and changing building structure and geometry. Stronger materials are better but more expensive. Minimizing exposed surface area helps too.
Students had three materials: paper towels, manila-type paper, and paper with toothpicks. Their challenge was to create model houses on a scale of 1 inch:10 feet quickly out of each material and position them on a "beach": a long, wide container half-filled with water and with sand on one end for a mini-coastline. Thanks to TeachEngineering for the plan.

Armed with six model houses (two from each material) the students placed their houses on the beach. We generated a scale-model thirty foot wave (video below shows how). Some houses were placed on sand 15 to 20 feet above sea level and were inundated. Toothpicks elevated other structures (some to ludicrous heights) and those fared better. Students observed how housing material and shape related to damage. They thought about the tradeoffs between material strength and cost, and between safe height and a height that occupants could actually reach!


Students did a wonderful job. They collaborated, practiced the design cycle (they were able to rework the buildings and have a second trial) and learned some STEM concepts. I'd say they also gained a better appreciation of the challenges engineers face due to tsunamis.

Additional resources: here's some recent tsunami survival design from a collaboration beteween Harvard and MIT: the Tsunami Design Initiative and SENSEable City.

Wednesday, March 9, 2011

Help Others with Your Skills

"I bought my first slide rule for $30 in 1956, which would be about $200 in today's dollars."

The look on the students' faces was priceless. I'm not sure how many had even heard of a slide rule, much less held one, as the wooden and decidedly un-electronic device was passed around. Dr. Kenneth Brewer began his guest lecture to our engineering class with a history of the technology that he used as a student, then as a doctoral candidate, then as a professor of engineering. When he asked how many in the class had calculators, there was only a smattering, since most of them use the calculator through some other device like a phone or ipod!

Our second guest engineering speaker of the year, Dr. Brewer taught Civil Engineering at Iowa State for over 30 years and is now retired. Students (and I) learned that in 1970 a calculator cost him $400! And that was from a discount store!

There are several obstacles to students choosing and sticking with engineering as a major. Yes, there's the math and science background, but there are a couple of other sneaky ones. It turns out that people study such things as student motivators, and have learned that 1) negative stereotypes of engineers and a 2) lack of knowledge of what engineers do are both harmful to engineering enrollment. Students need to hear, see, and wrap their brains around lots of positive role models and creative careers. Dr. Brewer was a fantastic example.

Aside from the slide rule, the coolest things he shared were stories and pictures from volunteer work he does with Engineering Ministries International, or EMI. EMI is a faith-based non-profit that sends teams of architects, designers and engineers to areas where they can help families and children through construction projects. We saw slides of a team next to a tank in Afghanistan and on a bus in India. How amazing for students to see that something they learn now can help someone across the world build a bridge, a school or a place of worship!

Dr. Brewer kept using words like collaborate, creative, listening and constraints. A constraint in design is something that is a boundary, something that you must keep in mind when doing your work, a line not to cross. His EMI trips ran into all kinds of constraints: environmental (work in India at night with a flashlight because it's 120◦F during the day) geological (sandy site in Jordan mean extra big concrete "feet" for support) and cultural (moving from province to province in Afghanistan required armed guides).

Even he "learned with a lone wolf mentality, the game has changed and it's a team now". Thanks to him for adapting and sharing his work with us.

Friday, March 4, 2011

Learn for Free

Geometry student's graphic repeat cell

This is an exciting time for education. Digital media and connectivity make it more possible than ever to learn what you want, when you want, applying it as creatively as possible. Here's a list of free resources that I've come across that can help both students and, well, I was going to say out-of-schoolers - but we really all should be continually learning at this point.
Free SAT, GRE and GMAT standardized test plans and problems. Has a nifty feature that can print you out an eight week study plan. Totally costless, has a thousand vocab words.

Classes from MIT
I spent one summer in high school studying at MIT and fell in love with it. Even though I went to University of Virginia, it's been in my heart ever since. MIT now offers many of its classes online FREE, calling it Open Courseware. Chemistry, economics, urban planning, engineering, it's all there. Some courses have notes only, a few have multimedia.

Classes from Everywhere
Organized by language, this site lists universities that offer Open Courseware similar to MIT's program. Notre Dame, Michigan, even Oxford's Mathematical Institute let you learn, self-paced, without cost.

Teach Engineering
Standards-based engineering lessons and activities, searchable and sortable by age and discipline. Great for encouraging students to think and collaborate, with lists of materials needed and how long activities should take.

The Art of Problem Solving's free, challenging and slightly addictive math tutorial. What I like about this site is that you sign up and are given a math problem to solve. If you get it right, the program bumps you up to harder problems. Get it wrong, and you'll work through more problems until you understand the basics. You score points and can compete, see your rankings, and if a whole class does it the teacher can view class stats. Many math disciplines treat subjects like silos, going deep into algebra or geometry but never mixing the two. An engineer might have an issue that requires algebra, geometry, logic and be open-ended; Alcumus comes up with problems that (in my opinion) more closely simulate the real world.
I've spent my share of time playing pointless but fun online games. This link gets you to more point-full games that integrate physics concepts, mechanical knowledge, and oh, by the way, are just as easy to fritter away time on. The only difference is that you'll be sharpening your mind.

Amazing lectures from TED
I've so enjoyed learning obscure, wonderful things from TED, a nonprofit that has as its goal sharing ideas. They invite speakers who are inspiring, strange and informative. In the last few days I've watched the world-champion whistler, learned about bioluminescence and saw a mathemagician.

That's probably enough for now. I've got tons more, if anyone wants particular help finding math vs. engineering vs. something else, let me know!

Wednesday, March 2, 2011

Designing Packaging

Test your packaging acumen - out of these solid shapes, given a volume of 12 ounces, which would use the least packaging?
Yesterday I gave the class a taste of packaging engineering. It made sense since we just finished a materials science unit with a focus on properties - the kind of stuff that wraps and protects the things we buy and use is vital!

Packaging engineers must be able to successfully integrate industrial or chemical engineering and work with a team of marketers, designers and financial types. Choosing the proper material, labeling it with the right colors, transporting it safely, while protecting the food or consumer goods inside is a complex task.

Take fast-food soda cups for instance. I'm a forgetful type, so when I've got that large drink of lemonade in my cupholder I'll often leave it there for, um, let's say a few days. The same cup that nicely brought lovely cold lemonade to my lips has, after 72 hours or so, begun leaking out of the bottom seam and depositing unlovely sticky lemon syrup in my cupholder. Why didn't the quick serve eatery make a better takeaway cup? Why not plastic instead of waxy paper?

Every paper packaging decision involves a trade-off. Fast-food joints could easily provide solid plastic take-out cups but the cost for plastic instead of waxy paper would be much higher. They could also design the cups with better paper to hold the liquid longer but that would take more money as well. The fact is, engineers and marketing teams have decided that for the given design goals of serving a beverage that (should be) finished and disposed of in a few hours a slightly waxy paper cup is just the right container. In some sense the fast-food cup is "designed to fail" at just the right time to save everyone money and reduce waste.

How about a half-gallon of orange juice? Now there's a product that won't usually be finished in a few hours, barring an attack of thirsty teenage boys. (Once I drank a quart of milk in one sitting but that was kind of gross.) The paper is thicker, more waxy, with a replaceable cap. It won't leak in a few days - but it won't last forever, either. It also has very cleverly designed features and colors to make you enjoy drinking it and think that it's fresh, usually pictures of trees and oranges and straws on the outside. You could have a great sturdy container of OJ but with drawings of candy on the outside and it wouldn't sell because moms would think it was full of sugar, even if it wasn't.

Now, which shape did you guess would use the least packaging? It's the sphere.

Students this last week listened to a lecture on surface area and volume, void space and efficient shapes. Even though the sphere has the best surface area to volume ratio (the least packaging to hold the most volume) we don't see spheres of juice on the shelves! Why? Not an engineering constraint, but a consumer use one - people don't want their soda to roll away! Also, spheres take up more room when stacked in a box than rectangular prisms do.

After the lecture, students worked in teams of about five with pieces of paper to design a paper cup that could hold the most volume of water for about a minute. With only one piece of paper at a time, the surface area was set but the volume could vary - and did! Designs that were rounded in shape seemed to work best, although plain paper without any coating would leak water within a matter of minutes. Still, if someone could engineering a paper cup that could be made by folding only, no glue or cutting needed, while still serving consumer needs, there would be much less waste and tons of money saved on manufacturing.

For more study check out these sites showcasing excellent design in packaging:

The Dieline

I.D. Magazine Annual Design Review
Science Blogs - Blog Rankings Engineering Blogs - BlogCatalog Blog Directory