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STC PROGRAM
Update
Fall 2004
Unexpected Results: A Teachable Moment
An experiment in the STC® Solids and Liquids unit
provides an excellent example of how science is far from predictable. During
the unit, students perform a variety of tests to help them define the
properties of liquids. The “drop races” in Lesson 13 are a way to
investigate how fluid or viscous a liquid is. When one STC® classroom staged
a drop race between shampoo and glue, the winner wasn’t the liquid that
students predicted.
Most students thought
shampoo would win the race. However, after staging several races the class
found glue was the overall winner. Why the different outcome? A common
student misconception may have been a factor. Most children have worked with
liquid glue, so they know from experience that as it dries it becomes
sticky, less fluid. Students may have assumed that glue is always more
viscous than other liquids.
Second, in Lesson 12 students observe glue and
several other liquids, each sealed in a plastic bag. As students mash and
manipulate the plastic bags, they see the glue actually sticks to the sides
of the bag, unlike some of the other liquids—again giving the impression
that the glue is less fluid.
Though the drop race results may not be what
students originally predicted, a teacher can reaffirm to students that
educated guesses are a part of science. The important thing is that students
record the data as they experience it, like true scientists.
When experimental results seem to conflict or are
inconsistent, have students recheck their outcomes or even conduct their
investigation again (if time and materials allow). Data can be acceptable if
they are consistent. If additional tests still offer inconsistent results,
encourage students to go back and review the variables of their test.
Solids and Liquids was designed for use at grades
K–2, so early elementary learners may not fully understand concepts such as
“variable” and “fair test.” However, the teacher can encourage students to
think about why the results varied (e.g., differences in the size of each
liquid drop, position of the drop, and temperature of the liquids).
Hands-on science is not always predictable. At
times, an investigation can raise more questions than answers! The
experienced teacher understands that unexpected results are an opportunity
for additional learning. These are gifts of teachable moments. Use them to
introduce your students to the fascinating world of science.
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