Life is full of risks. When we walk along the sidewalk or across the street, we run the risk of a vehicle striking us, tripping on a crack, or having a meteorite fall on our heads. Each of those hazards has a different probability of occurrence. On particular streets in any city, it is more likely that you will be struck by a vehicle than on other streets. On the streets of a city, the probability of being struck by a vehicle is greater than if you were on the streets of a small town.
There are probably some towns in Saskatchewan where no one has ever been struck by either a vehicle or a meteorite. That doesn't mean that those events have the same probability. In any urban area of Saskatchewan, it is less probable that you will be struck by a meteorite than by a car. If you are boating on Besnard Lake, it is more likely that you will be struck by a meteorite than by a car.
Another set of probabilities expresses the likelihood of injury resulting from an incident. How great a danger is produced depends on many factors. If you are struck by a vehicle, the speed of the vehicle, the type of vehicle, your physical condition and agility, and the surface on which you land are all pertinent variables. Fewer variables are important if you are struck by a meteorite. These are some of the concepts which will be considered by students in this unit. They will explore the meaning and determination of probability. They will analyze their lifestyles to determine the risks which they are assuming in both voluntary and involuntary activities.
Science writing and reading activities, as discussed in this Guide, should be incorporated into each lesson. Writing helps students assimilate what they have seen, heard, and read. It gives them a chance to reconcile their ideas with what they have encountered in the activities, reading and discussions of science class. The phrase 'writing to learn' indicates the purpose for including many opportunities for students to write during and about science classes. Vary the modes and formats assigned. Give them an opportunity to read from a wide variety of sources so that they can be exposed to many ideas and different ways of expressing ideas, and as a model for their own writing. The best model for an assignment to write a newspaper editorial on a topic is an actual newspaper editorial on a similar topic.
Science challenge, as described in this Guide, is meant to extend students' critical and creative thinking abilities in the context of the science concepts being studied. Activities involving science challenge are included in the Suggested activities section of this unit and should be incorporated into science lessons. The challenge is intended to give each student a chance to investigate an area of interest in more depth than would be possible for all students in a class to do. Science challenge is a key strategy for bringing the Adaptive Dimension to the classroom, and for encouraging independent learning.
No related concepts dealt with in K-8 science have been identified. However factors B19 and C10 relate to the concepts, as does preparatory work in mathematics.
1.2 Relate the concept of probability to the concept of risk.
1.3 Compare risks of various voluntary and involuntary activities.
2.2 Assess significance of contaminants in water supplies.
2.3 Recognize how scientists estimate toxicity levels from experimental data.
2.4 Discuss how the value one places on an activity influences the amount of risk one is willing to accept.
3.2 Understand the potential narrowness in adopting a single perspective in judging the impact or influence of objects, experiences, or events.
3.3 Explore how moral values influence behaviour and assessment of risk and benefit.
3.4 Recognize the importance of fact-finding, prior experience, and open dialogue in the development of reasoned arguments.
3.5 Establish arguments based upon human rights, human needs, or needs of the environment when examining social issues.
Note: Many of the resources listed in Science: An Information Bulletin for the Middle Level - Key Resource Correlations describe activities or ideas for activities.
From the background research done by both sides for the
debate, construct a poll which will assess people's level of
knowledge about radiation, how radiation is used to generate
electric power, and the issues which are important in the
discussion of the use of nuclear energy to generate
electricity.
Select a sample to answer the questions, administer the
poll, analyze the answers and present the results. Devise a
program which will educate the public about nuclear power
generation and the issues surrounding it.
Factors: A3, A8, B5,
B19, C2,
C17, D5, D7,
F5, F7,
G3,
In Canada, the 1986 death rate for females was 486.9 per 100
000 population. This means that 1 of 205 females in Canada
died that year. If you took a sample of 205 Canadian females
living on January 1, 1986, does this statistic mean one and
only one of that sample will die during the year? Explain
what the statistic means. What influences whether one
particular person will die during a specific year?
The death rate for females dying of influenza and pneumonia
in 1986 in Canada was 17.3. What percentage of females who
died in Canada during 1986 died of pneumonia? If there were
13.5 million females living in Canada during 1986, how many
died of influenza? If you took a sample of 1000 women living
in Canada on January 1, 1986 how many of them would die of
influenza or pneumonia during the year?
Factors: A6, B8, B19,
C10, C17, D5,
F5, G1
Toss the coin fifty times, recording the result of each flip. Draw
a line graph to show the percentage of heads which have been
recorded after 5, 10, 15, 20, 25, 30, 40 and 50 flips.
Trade jobs within each pair and repeat. Graph the data for
the second round of flipping on the same graph as the first,
using a different colour. How do the shapes of the curves
compare. Submit the number of heads produced from the pair's
100 flips to the teacher so that a class report and results
can be compiled.
Predict the shape of the graph and the number of heads if
you were to flip the coin 200, 300 or 1000 times. Why is it
unreasonable to use the result of the first three flips to
predict the final percentage of heads which will be
produced?
Factors: A6, B5, C10,
C15, D5, F5,
G3
What was the percentage increase in foodborne diseases in
New Brunswick from 1983 to 1984. See if you can find out
what happened in Saskatchewan in 1983 to make the rate for
that year so high? Try to find more up-to-date data.
Write a newspaper editorial explaining the use of statistics
to predict events. Explain how the variability in the event
and the size of the population from which the information is
taken make a difference.
If the above data is expressed as risk data, the rate of
deaths from high school football is 10 deaths per million
players. The rate for pro football is 800 deaths per million
players. From these data, which sport appears to be the more
dangerous? What is the difference between the appearance in
the total number of deaths and the rate per million
participants?
Although December and July both have 31 days, the average
amount of sunshine during December is 83.9 hours and in July
is 342.2 hours. What factors would be responsible for this
difference?
What is the chance that the hour between 7 p.m. and 8 p.m.
on December 22 will be sunny? What is the chance that the
hour between 7 p.m. and 8 p.m. on July 22 will be sunny?
Sunlight hours in Regina accumulate during an average of 320
days of the year. What is the chance that there will be some
sunshine next February 17? What is the chance there will be
no sunshine on February 17 next year?
Distribute the Risk Data sheet
Calculate the
numerical risk per 100 000 persons, using the Statistics
Canada data given. Rank the hazards according to the risk as
expressed by this number. Compare this ranking with the
rankings done in the first part of this activity
Why isn't the estimated population at risk the same value
for each risk listed?
Heart disease is a lower risk for the 10-19 year age group
than for the population as a whole. What other event or
activities might pose a lower risk for this age group? Which
might pose a higher risk? Be prepared to give reasons to
support your statement.
Discuss the reasons for the variations which show up in the
Risk chart. Suppose that the numerical risk of injury from
jumping from a car moving at 30 kph is expressed as 50 000
in 100 000. Express that risk as a probability for each
person jumping from the car.
Numerical risks that are expressed in the form "1 chance in
2" are called risk probabilities. They can be calculated
from the numerical risk data. Calculate risk probabilities
to fill in the Risk Probability chart, using data from the
Numerical Risk chart. Several cells are completed for you to
be able to check your method of calculation.
The injuries to these people were categorized as minor,
moderate, or major. Of those injuries to people wearing
seatbelts, 1 750 were minor, 2 824 were moderate,
and 479 were major. Of those injuries to people not wearing
seatbelts, 214 were described as minor, 549 as moderate, and
307 as major. Present this data in a table showing both
absolute numbers of casualties and the risk probability
statistics for each group of people.
Write a paragraph summarizing your conclusions and
recommendations from analysis of this data.
Then compare the costs and benefits of an involuntary
activity such as the risk of homicide. How can the number
and relative worth of the costs and benefits be changed?
Finally, use data from the Deaths in Canada table and
Accidental Deaths in Canada table to complete the numerical
risk and risk probability equivalents of those charts. Discuss
some of the questions
that arise from the data. Why do the numerical risks vary so
much from cause to cause and from group to group? Why are 15
to 19 year-old males 9 times more likely to die accidentally
than 10 to 14 year-old females? Why is cancer more prevalent
in males?
Objectives: 1.2, 2.4, 3.1, 3.2, 3.3, 3.4, 3.5
Assessment Techniques: peer assessment, anecdotal
records, oral assessments
Instructional Methods: debate, research project,
surveys
Objectives: 1.1, 2.1
Assessment Techniques: written assignments, short
answer test items
Instructional Methods: explicit teaching, problem
solving, reflective discussion
Objectives: 1.1
Assessment Techniques: written assignments, presentations,
short answer test items
Instructional Method: didactic questions
Predict the number of cases and the frequencies during 1984.
Then hand out the 1984 chart so
that students can check their predictions. How reliable are
predictions based on one set of data? 
.
News from nutrition studies is everywhere - TV, radio, newspapers, magazines and even food packages. Just because a study is reported, doesn't mean it applies to you. But, how do you tell if such claims are the "truth"?
A study can refer to any research test. Every year tens of thousands of nutrition studies are published in English Alone. Major journals in the medical and nutrition fields review any article submitted to them. This helps to limit any overstated or unproven claims. Even when a study appears in a respected journal, it doesn't mean something has been "proven". One study, on its own, cannot prove or disprove anything. To be valid, anyone anywhere should be able to conduct the same research and get the same results.
Many studies are announced as major breakthroughs. Yet, "astounding" advances are rare. A study may be too small or too short to mean a lot. It is simply another small piece of a big puzzle. Consider a 6-month study of 12 men which showed that eating Food "X" increased their risk of cancer. There are several reasons for caution that surface when assessing the impact of this study. Six months may be too short a time period to show an increased risk. A study of a small number of people may show need for further research more than cause and effect. We cannot assume that several million people, both male and female, will react in the same way as these 12 men. Lastly, there could be many other reasons why these men had increased risks. What known risk factors did they have? Did the study check into their smoking habits, occupational hazards, or dietary fat and fibre intakes?
Scientific studies are written using words such as "may" rather than "will", "suggests" rather than "proves" and "is linked to" rather than "causes". Changing daily habits because of a single study is not a good idea. On the other hand, guidelines for healthy eating from major agencies such as the Heart & Stroke Foundation, Cancer Society or government health departments are based on many studies which support their advice.
When you hear of new nutrition research findings, there are a few things to keep in mind. No matter how much hoopla surrounds a report, wait to see what the experts say in the coming weeks and months. Remember that results from single studies will not stand on their own but must be repeated by others for confirmation. (Remember all the fuss about generating nuclear power in a jug of water on your kitchen table? No one else could repeat it.) Also, beware of any research finding that is used to sell a product whether in ads, on labels or by word-of-mouth.
This doesn't mean that all studies are faulty or that research is not to be trusted. Many reported studies have merit but are of interest only to other researchers. Results may not be enough on which to base lifestyle changes. In short, it is unwise to generalize from a single study. Scientific progress is slow and steady, not a series of dramatic breakthroughs.
Written by the Public Health Nutritionists of Saskatchewan. Reprinted with permission.
