| Investigative Demonstrations
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| While demonstrations are an integral part of effective science education, too many students view it merely as an entertainment break in the class schedule. They do not pay attention to the details, do not learn the important aspects intended to enhance the conceptual understanding of the material being covered and they do not retain much of what occurred. Over the years, I have evolved a process that addresses all three factors that I refer to as investigative demonstrations.
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| Prior to starting a demonstration, I distribute a sheet to each team of students. The first part is merely a set of lines for them to record their names. The second region is titled “Hypothesis”. The third is titled “Observations”. The final region is titled “Explanation”. After they have written in their names, I intentionally give a brief, incomplete description of what will be done in the demonstration. I am interested in what their hypotheses are, letting me see where they were prior to carrying out the demonstration. They understand that their hypotheses do not need to be correct. They will receive credit as long as what they write is valid for the limited input they received.
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| I then carry out the demonstration. They need to pay attention and then, as a team, record what they observed. This builds up their team work and their attention to detail. One grade will be given to everyone on the team, so they all have a vested interest in contributing and being sure that nothing was left out.
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| Once they have recorded their observations, they need to work together to explain what happened. This is the stressful period for me as I walk around the room, listening to their discussions. I want to comment and offer suggestions, but I must withhold any comments during this session.
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| When each team has handed in their sheet, we then discuss what occurred in the demonstration. I add missed points and correct explanations that were erroneous or concepts that had been missed. The students usually bemoan the brief description they had been given prior to the demonstration, complaining that it was misleading, but they gain more from this experience.
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| The sheets are graded in a simple manner. As long as they are complete with decent attempts, their grades will not be affected. If a team has paid better attention to observation details or has a better explanation than other teams, they can earn points that are added to each member’s grade. This has proven to work well as a motivating force, as “extra credit” always entices student effort.
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| While this process takes more time, both in class while carrying out the demonstration and afterwards in reading and commenting on their sheets, I find it to be totally worthwhile. This investigative process makes the demonstrations meaningful and the students gain in several different ways, justifying the invested time.
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