Chapter 3, “Chance Affects Decision Making,”
introduces students to the idea of probability. Probability
relates to technological problem solving because people use
probability when making decisions. The activities in this
chapter help students to see how understanding the chances of
different events occurring can help people decide what action
they should take. Probability is also based on patterns. In the
previous chapters in this module, students have learned how
patterns can help scientists understand weather phenomena.
In the Engage activity, What Will the
Future Be?, students will express their ideas about the words prediction
and forecast. They will begin to think about
probability when they recognize that weather forecasts often use
words such as “a chance of” or “the possibility of.”
These words reflect some degree of uncertainty.
The Explore activity, Yes, No, Maybe,
focuses on how different words that people commonly use indicate
chance or probability. Students will sort words using two scales
that range from a low chance to a high chance of occurrence.
In the Explain activity, Probable
Outcomes, students will build on their ideas from the Explore
activity as they are formally introduced to the idea of
probability. They will use a simulation to learn about the
probability that certain weather events will happen.
In the Elaborate activity, What Will
Happen Here?, students will use probability to decide which
events are most likely to happen in different locations.
Finally, in the Evaluate activity, You,
the Decision Maker, students will analyze information about the
probability of different events occurring, and make
recommendations to a town that needs to solve its water problems
caused by drought.
Students may harbor misconceptions about the material they
will be studying in this chapter. Some of these misconceptions
are listed in this section (American Association for the
Advancement of Science, 2001). Do not take time to go through
them as a list of lecture topics for your students, but rather
use them to inform your teaching as they emerge. Many activities
included in this chapter work to expose misconceptions and help
students develop better mental models.
Some common misconceptions include the following:
Probability is influenced by the most recent history.
For example, students may assume that a coin that has landed
on heads several times in a row has a greater probability of
coming up tails the next time. Or, that the numbers in a
winning lottery jackpot last week are less likely to come up
this week. In reality, each time a coin is flipped, there is
an equal chance that it will be heads or it will be tails. For
each lottery drawing, all numbers have an equal chance of
being drawn.
Events with a high probability will definitely occur.
Even in cases where there is a high probability associated
with an event, it may not actually occur. In situations where
the probability is high (for example, 90 percent), on average
the event would occur 9 out of 10 times. In contrast, even in
situations where the probability is low, the event may still
occur. If there is a 1 percent chance of a specific type of
event occurring, we would expect that event to occur an
average of 1 time out of every 100 times.
Models are physical copies of real things. Students
tend not to think of models as conceptual representations.
They often have difficulty with the idea that a model can be
tested by comparing its implications to actual observations.
Although middle school students recognize that models may be
changed, they often view this as fixing what is wrong with the
model instead of using it as a tool to represent and predict
events.
For several of the activities in the chapter, you will need only
24 hours of advance notice for preparations. You may need
additional time to gather materials for the Explain activity.
You might want to work through the It’s
in the Bag simulation in advance to become familiar with the
activity.
See the Advance Preparation sections of the activities for
details on the necessary preparations.
