In the lab, Science is always, or at least should be, approached using a "hands-on," discovery method! Here, I intend to use the term hands-on to mean "To do Science, at any grade level, is to engage in an activity during which students manipulate their environment under the supervision of the instructor." I intend to use the term discovery to mean "The students are expected to learn by observing the results of the activity, without the expectation that there exists an inherently correct answer beyond the observed outcome." The implication of this definition of discovery is that the teacher is not required to know the answer, because the 'correct' answer will be discovered (perhaps by the teacher at the same time as by the students) during the activity.
It has been my experience that it is generally easier to determine the answer by first
determining what the question is. Hence, I recommend that the first step in any hands-on,
discovery activity for Science is to ask a question. Not any question will do, because the
"rules" of Science expect us next to guess what the answer ought to be. If I am going to be
expected to guess the answers to my own questions, I prefer to ask simple questions. As a
general rule, I would suggest that when young children begin their questions with the word
'Why,' they are warning you that a difficult question will
follow. You will need two skills to divert their difficult questions:
(a) you can change the subject, or
(b) you can change the question to a simpler question.
When you have determined that the question may lead to a promising experiment [when
scientists do a hands-on discovery exercise, they call the activity an
experiment], you will want to change the question to a simpler question (beginning
with other key words, such as 'which - what - when - where -
how').
For example, Why do cats purr? could be restated as When do cats purr? Think
about these two questions: how would you prove that your answer to the first is correct?
And, how would you prove that your answer to the second is correct? Which of the two is the
simpler question to answer [and to develop an experiment to test]?
After sufficient practice [especially in front of a room full of eager young students],
you will become proficient in asking simpler questions. If all else fails, you can always
answer the question with a question {which is often an excellant pedogogic device):
"How could we find out?" and then let the students design an experiment for you. We
refer to the particular skill-development of asking simpler questions, in the college-age
student population, as critical thinking, which is at the top
end of Bloom's cognitive skills.
So, before attempting an experiment, you will need a question.
If you can not state what your question is, you are probably engaging in a "science-themed,
non-science activity." The most likely science-themed, non-science activity will be either
a science-themed arts/crafts exercise or a science-themed reading exercise.
Having, then, specified a question [which is 'interesting' by the definition in section 1.1
the Nature of Science, Scientific Thinking], we are expected by scientific methods to
guess what the answer ought to be (we spell guess
"h-y-p-o-t-h-e-s-i-s" hoping that non-scientists will be impressed because guess is a single
syllable, while hy.poth'.e.sis has four syllables; implying
that we must be at least four times as smart). You should not worry about how 'good' your
guess is, because we expect to determine whether or not our hypothesis is right by observing
the results of an experiment.
Once we have guessed what we expect the answer to be, our hypothesis, we ask two standard
questions so we can design the experiment:
(a) what would happen if our hypothesis were true? and
(b) what would happen if our hypothesis were not true?
If you were to become a serious scientist (rather than a teacher of future scientists), you
would want your hypotheses (plural of hypothesis) to predict
some observable event which should occur if conditions are met, but should not occur if
conditions are not met. This is why we insist that scientists state their hypothesis; a
correctly worded hypothesis will also describe precisely what the experiment seeks to
find in order to determine whether or not the hypothesis is true.
You should note that, once you know what observable event should happen, the experiment
becomes a "simple" matter of watching to see if the predicted event does occur. The "best"
science experiments include
- an experimental group [where conditions are met], and
- a control group [where conditions are not met]
If the expected event does occur in the experimental group AND does not
occur in the control group, we get to conclude that our experiment was a success and the
hypothesis is true!
However, if the expected event does not occur in the experimental group OR
does occur in the control, we have to conclude that our experiment was a success and the
hypothesis is false.
Either way we proved something!
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© 2004 TwoOldGuys™