No-Mark Labs
The idea behind no-mark labs is to encourage students to be creative
by removing any penalty for a poor end result and discouraging
students from following "tried and trued" methods.
A common problem for students is the conflict between creativity and marks.
If a student wishes to be creative in their schoolwork, they will ultimately
have outcomes which yield high marks and those which yield lower marks. This
is part of the learning process. Unfortunately, some students feel that they
cannot "afford" these lower marks. In constantly focussing on the highest
marks possible, a student will become less creative and adventurous.
I have seen too many straight "A" students with no creativity or courage.
Unable or unwilling to extrapolate on their knowledge, if you ask them a
question, all you get is the textbook answer. These students are thus unable
to teach or do research, and become as useful as the textbooks they have
memorized. This problem is pronounced in classes with competitive or highly
ambitious students whose first priority is to get high marks. In light of
the two conflicting goals, creativity and marks, a teacher must take the
marks out of the equation to emphasize creativity.
Many prospective medical students are forced to strive so hard for marks
that they banish all creativity. Medical schools must take these students
and train them to be creative doctors. One way in which this is accomplished
is via no-mark labs*. Students are put into the lab to learn about conditions
and the tools to treat these conditions, but with a twist. They are not
given enough information prior to the lab to be able to fully understand
what they are doing. The result is that they leave the lab with many
questions. They are encouraged to postulate hypotheses to the questions
which are answered in lecture the next day. I would like to provide a
couple of examples of how to accomplish this same result in a high school
setting.
Set-up:
Begin by telling the students that they have not yet been taught enough
information about the experiment they are about to perform. Tell them that
you do not care if they get the right or wrong answer, but that you are
looking to see HOW they get to their answer. If a student gets the right
answer by guessing, then it is meaningless. If a student gets the wrong
answer, but can justify their conclusions as well as a student who got the
right answer, then they both did equally well. You can give the students
bonus marks to work on this problem; you can give them a fixed amount of
marks just for trying, regardless of the outcome; or you can give the
students some other incentive.
Experiment 1 - Osmosis:
Students must have a basic understanding of osmosis prior to this
experiment. Perhaps as little as just knowing that salt "attracts" water.
Materials:
Two beakers, one with salt water, the other with tap water
Two potato slices, about the size of a chunky fry, one in each beaker.
Tell the students that one beaker contains a potato in salt water and the
other contains a potato in tap water. They are not allowed to taste the
water. They are just allowed to use their eyes and hands to determine which
potato is in salt water and which is in tap water. They can look at the
potatoes, they can bend the potatoes to see how flexible they are. In the
end, you want to see the reasoning they used to determine which potato is in
the salt water. Encourage the use of labelled diagrams.
The potato in the salt water will dehydrate because of the salt, and will be
softer than the tap water potato. The students should be able to come
up with several reasons why one potato is softer than the other, but they
should all focus around effects by the salt. Whether it be that the salt
diffuses into the potato and makes it swell, or that the salt draws water
out of the potato doesn't matter, as long as students are thinking
creatively. As a follow up, you can ask students why the tap water potato
gets more rigid than a freshly cut potato (it aborbs water). You can also use
this lab to demonstrate why plants have cells walls (to allow them to
pressurize their cells without exploding) and why thirsty plants wilt (they
don't have enough water to maintain pressure).
Experiment 2 - Reverse Engineering:
Have the students draw you a flow-chart or some other diagram of how a
household appliance works. Once again, you are not necessarily looking for
the right answer, just a good answer. Encourage detail. You might give the
example of a hair dryer. Describe how the fan blows the air past the heating
element. Then go on to show how the air intake has (usually) a mesh to avoid
large particles getting sucked in and talk about the different types of
attachements such as diffusers to change the airflow. The objective is not to
look in a book or ask a parent, but to look at the object, and find out what
each part does, and why it is there. Let each student find their own
appliance but try and ensure that they don't do something too complicated.
In the end, compliment all the students on being courageous. It is difficult
to stick out your neck on something you are unsure of, but that is how
science works - you have a question, and you must formulate hypothesis. As
you tell the students the right answer, reassure them that they did not have
enough information to come up with this answer themselves, and that the
final answer isn't what matters, but the method to reach that answer is what
counts. While the students may have to make some risky assumptions
to describe the experiments, outright guessing should be discouraged.
* The University of Medical School uses no-mark labs as
described in the preamble
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