Last week was very busy- we taught several classes. On Wednesday, River Classroom was back at New Mexico Wildlife Center for an Engineering Design Challenge! One of our goals for the class is to develop working wind turbines and water wheels that we can hook up to a generator. This really demonstrates how mechanical energy can be converted into electrical energy. In order to build these devices, we have to have a plan, and what better way to develop a plan than to let your class do the work?
The instructions we gave the students were simple and went something like this:
“Over on that table, we’ve provided you guys with a variety of materials. Take these and create a model of a wind turbine or a water wheel. You have until 1 pm. Go.”
Our students are very smart, and we knew that they could rise to our challenge- turning these random materials (plastic bottles, drinking straws, wooden dowels, pins, corks, and a variety of containers from the recycle bin) and creating a model of a wind turbine or water wheel that really works.
We recognize that not everybody likes to work in a group, so we let the students decide if they wanted to work individually. We also voted on the best number of people to have in each group so that everybody gets a chance to do something. Eventually we had 5 groups, with anywhere from 2 to 4 people per group.
Three groups worked on water wheels, while two groups constructed wind turbines. The range of designs was spectacular! Once again students were not required to have a finished blueprint before they began, but they did need to have an idea of what materials were needed.
As the activity progressed, students began testing their models, with varying degrees of success. Everybody had a few modifications at first.
As time progressed, the models improved and became more efficient.
It was a very cold day, so most of the initial tests took place inside.
Eventually some of the braver students ventured outside for further testing.
By the end of class, nearly every group had a working wind turbine or water wheel. Some designs worked better than others, which turned into a review of the concept of efficiency. As part of their reflections, students had to draw a detailed blueprint of their model.
The variety of designs that our students can come up with given very little instruction never ceases to amaze us.
After all of this engineering, a few groups demonstrated their water wheels for the class. Part of their reflection in their science notebook was to describe the types of energy used in their model and to list how energy was lost in the model (referring to our discussion of efficiency).
Here are a few excerpts:
“Kinetic: When the wind blows on the “wings”, they start to move.”
“Friction happens when the plate touches the cork and the spindle. I know because it causes heat.”
“Our water wheel uses mechanical and gravitational energy. When the stick is moved it creates mechanical energy. When the plate is filled with water gravity brings it down.”
We are looking forward to continuing work on these models and to building a real version in the next few months!