2 Replies Latest reply on Aug 2, 2014 1:05 PM by glen_w

    STEM Snacks – One plus One equals what?


      This summer I helped train science teachers in Utah. We focused on our core standards and using technology to engage students. During the trainings, teachers often reminded us “one plus one equals two.” This usually started a discussion about how changing a teaching method is not needed. (In other words … we’ve always done it this way, why should we change?)


      I did a quick online search for “one plus one does not always equal two.” I recognized these teachers might not accept a web page as a reputable source.

      Teachers explored the result when 100 milliliters of water was added to another container of 100 milliliters of water. (Cue “Doh” sounds.) No one was surprised when the resulting volume was 200 milliliters. Teachers measured out 100 milliliters of water and place it into a container. They then measured out 100 milliliters of alcohol. The alcohol was poured into the water container. Teachers began questioning “why” these results. The goal was to drive “inquiry” and I called this a success.


      Based on this, I ask for your suggestions to the following:

      • What other “unexpected result” experiments have you had students do?
      • What student interest activities lead to the best questions?
      • How can inquiry questions lead to better student writing?


      (Image source: http://upload.wikimedia.org/wikipedia/commons/thumb/8/8f/Lab_wash-bottles_water_EtOH.jpg/666px-Lab_wash-bottles_water_EtOH.jpg)

        • Re: STEM Snacks – One plus One equals what?

          Yes, it is like adding grape nuts to cheerios. A few discrepant events I use include:

          1 (gravity/mass/inertia/air resistance) dropping a book and a flat sheet of paper from the same height, then repeating by placing the sheet of paper on top of the book and also by crumpling the piece of paper and dropping it side by side with the book; what will land first - book or paper.


          2 (gravity/path of a falling object) place two small containers a few cm apart at end of a meter stick; place one marble in container closest to end; lift ruler at angle of about 30 degrees and drop ruler; what path will the marble follow?


          3 (air pressure/Bernoulli's principle) transfer cotton ball from one paper cup to adjacent cup by blowing a puff of air across top of cup with cotton ball


          4 (probability) The Monty Hall or Three Door Problem: Game Show Problem | Marilyn vos Savant


          Of course, other unexpected results come from the experiments students conduct when they find their hypotheses are wrong. When my students conduct experiments, I require at least two groups to test the same question. Sometimes the results do not match and these unexpected results lead to productive discussions.


          The best questions tend to be the ones the students come up with themselves. Many times the questions are beyond what we have the tools to test, so we have to make the questions manageable. Often, I will give the context and the students will come up with the specific question. For example, I have a spinning top game called Battling Tops; student groups come up with questions they can test, such as which top will spin the longest, is a top more likely to get knocked out of the arena if battling one other top launched directly at it or at a 90 degree angle, etc. (those are examples of student generated questions that they actually tested).


          Inquiry questions can lead to better writing because there is a higher interest level. I still struggle getting a significant number of students to go beyond the hands on and actually write with detail, clarity, and accuracy, but it is clear to me that if student interest is high, if discrepant/unexpected events/results are involved, students are apt to write more and better. What also helps with the writing portion is student feedback. The teacher I work with is very good about requiring students to make written comments about student work (we have a wiki with student work). A student might comment about data that are questionable, sentences that are awkwardly written, poor grammar, a procedure that is confusing or quite clear, and so on. The authors are responsible for responding in the comment section of the wiki and making any necessary revisions.


          Here is a really cool unexpected result from Numberphile:

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