Saturday, July 8, 2017

Summer Science Night #1 - July 2017

On a hot night after work this week, I spent a pleasant hour or so with a couple of comrades as we visited a low-income apartment complex.  We were there to lead some kids through a science activity dealing with low-tech water purification.  One of our number has a background in civil and environmental engineering, and she showed the kids how to construct a water filter using empty plastic bottles, coffee filters, sand and gravel.  She gave a short presentation on why water purification is important, and the danger of water-borne disease and exposure to man-made toxins that can result from drinking unfiltered water.  Then we all began constructing our filtration devices. 

We tried out our filtration devices on some "dirty water" that we (the adult teachers) had made out of water, food coloring, oatmeal, and two-year-old white rice.  We measured how much each person's filter was able to pass in a one-minute period, and then led the kids through a few equations to figure out how long it would take each kid's filter to pass a gallon of filtered water.  I talked to the kids about how much water an average person needs to consume in a day, and how they could tell whether they had drunk enough water for the day.  (Hint: if you wake up at 2 in the morning with a horrible leg cramp after doing a lot of work under a hot sun, you know that you didn't drink enough water.)  We also asked the kids to think about the relationship between how much impurity the filters removed versus the flow rate of the unfiltered water through each filter, so that they might consider whether a fast filter was more effective than a slow one.  Lastly, we talked to them about how dirty water could be pre-treated before filtering by letting it sit for a while so that heavy impurities could settle to the bottom of the water container.  They also learned a new word, "turbidity."

The activity seemed deceptively simple, yet it managed to hold the attention of the kids, most of whom were between 10 and 12 years old.  We also had a couple of adults join us, including the mother of one of the kids.  Below are some pictures of what things looked like:


This is the friend of mine who led the kids in constructing the filtration devices.  On the table behind her is a partly-completed filtration device.



Here are a few adults and kids comparing the turbidity of their filtered water samples.




 Here is another view of our participants comparing the turbidity of their filtered water. 

We will have four more summer science sessions at the apartment complex, and at least one other session will involve water purification.  This last week's lesson was a lot of fun for everyone, and it was yet one more important step in building alternative arrangements to bring math and science education directly to people who need it, right in the settings where people live.  We thus find ourselves following in the footsteps of other artisans who have brought their work directly to people right where they live - as is the case for buskers and those who perform house concerts, as well as the pioneers of the original "flying universities."  It is exciting work.

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