Friday, March 1, 2013

Models and Learning by Doing or How Design Failures Can Teach the Best Lessons

Today, I and a couple of volunteers went into the 2nd grade classroom and had the students build models of satellites.   The students have already had "changes of state" lessons in which they learn about solids, liquids and gasses.  Building off of that, I use the activity from teachengineering called Beat the Heat.
In this activity, I talk to the students about models.  We talk about how you can build a model car out of legos, or build a model airplane.  It is not the same as the real thing, but that you can build and test aspects of the design.  Today, we used plastic eggs as a model for the shell of a satellite that we want to send to Venus.  Venus is a hot planet reaching temperatures of 1,300 degrees Fahrenheit.  We talk about what kinds of things you would want to learn about Venus, so we decide a camera is one of the most important things you would want in your satellite.  Instead of using a camera in our test, we use butter.  The idea is to give the students a pat of butter and have them protect it from heat.  We also give the students various materials to use such as tooth picks, cloth, packing peanuts, cotton balls, balsa wood.

The students then design and build their satellite model using these materials.  

Next, they draw and label their designs.

Finally, I use box fitted it with a hole for a hair dryer for a heat source, with a thermometer and a viewing window with egg cartons in the bottom for holding eggs.  I then turn on the hair dryer and heat the box to 160 degrees F.   This is our Venus simulator or testing rig.

After the temperature in the box reaches 160 degrees F, we take apart the eggs and look at the results.

We learn that if the butter is kept away from the surface of the eggs, it generally survives, but if it is in contact with the egg, it will melt.

In the second of the six classes I ran this exercise with today I had one group whose butter completely melted.  The group was pretty dejected, but one of the other students spoke up and said,

" Don't worry.  Ms. Skalak told me last year that failing was a learning experience.  Last year when we built water filters I ended up with sand all in my water.  But, now I know better how to design the filter."

I asked the student if he remembered it more because it didn't work out as he had hoped, and he said yes.

Learning by doing is a great way to get the students to learn a concept not just with their head, but with their whole being.  I think this student learned many lessons last year:

  •  he will never put sand in a water filter without something to hold the sand in the filter such as cloth or screen
  • the failure of his design was a bit painful at the time, but it is something that engineers have happen all the time
  • it is okay to fail, because it gives you an opportunity to learn and make it better

Are the students going to run out and build a satellite for NASA based on these ideas?  Of course not, but if they can learn something like this student did about failure, and the opportunity to learn something from the failure.   I think the exercise is more than worth it in time and effort, and besides, it is just fun to do.

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