Students should also identify the chemical names of substances used in everyday life, and appreciate the dependence that Canadian society has on both natural and synthetic chemicals. The trend from total reliance on natural chemicals to the dependence on both synthesized and natural chemicals should be investigated.
Science writing and reading activities, as discussed in this Guide, should be incorporated into each lesson. Through reading from a wide variety of sources, students are exposed to differing viewpoints, differing modes and styles of explanation, and the underlying message that there is not one book where one can find all the information one needs. Magazines, student science journals, and narrative nonfiction are all sources for student readings. Through writing in a wide variety of modes and formats, students refine their understanding of the concepts of science and develop their ability to communicate through the written word. Offer your students the opportunity to write as often as possible.
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 should be incorporated into science lessons in each unit. Many of the suggested activities in this unit are science challenge activities or provide opportunities for extensions which challenge the students. 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.
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Note: Many of the resources listed in Science: An Information Bulletin for the Middle Level - Key Resource Correlations describe activities or ideas for activities.
Factors: A9, B1, C4, C12, D3, F2, G3
Objectives: 1.1, 1.2, 1.4, 1.8, 3.4
Assessment Techniques: self assessment, extended open response test
items
Instructional Methods: reflective discussion, research projects,
explicit teaching, reading for meaning
Factors: A9, B14, C4, C10, F2, G1
Factors: A1, B13, C4, C12, D3, F5, G2,
Use the codes on containers to help create a list of uses of each type
of plastic. (A starter - 4 LDPE bread bags) Create a display with samples
of the various types and formulations of plastics.
Why do so many of the names of plastics use the prefix poly? Why
do the names of so many end in ene?
Creativity, usefulness, aesthetic appeal, amount of waste plastic produced,
the advertisement, and the name given to the product are the criteria by
which the products will be judged. Recruit another science class to come
and judge the objects. Each object should be displayed together with an
advertisement which explains and promotes the use of the object.
A sample evaluation sheet which the students of the other class can use
to grade the objects is included here. If one judging form is given to each
pair of students, discussion of the criteria is promoted.
Devise an investigation to determine whether the direction of the lines
has an effect on how the plastic stretches. Identify as many pertinent variables
as possible, so that your experimental design can account for them. Obtain
another square. Devise an investigation to determine how the temperature
of the plastic affects how it stretches.
Another way to illustrate the polymerization of ethylene to polyethylene
is to have students standing in pairs with both hands joined. Ask the students
to start walking around an open area. When they bump into another pair or
group they must drop one hand link and join it to one member of the other
group, each end of this new groups leaves a hand unattached to link to the
next group to bump into the chain. If you wish, the teacher can act as a
polymerizer, when the teacher touches two groups simultaneously, they must
polymerize.
Look under the car at the exposed chassis. Do you see any evidence of
corrosion there? How does the prevalence of corrosion there compare with
the prevalence of corrosion on the painted areas of the vehicle?
After a minute, take a pencil point and poke a small hole in the latex
at the tip of the finger. Then roll the latex upwards along the finger to
form a band of latex. Remove this band and let it cure for several hours.
Next class, design tests to determine the elasticity and strength of the
latex bands formed. Conduct those tests. Can a way of producing stronger
or more elastic bands be developed?
Cut the filters into rectangles about twice as long as they are wide,
with the width such that it is about two-thirds to three quarters of the
height of a wide mouthed clear glass jar. Medium to large sized canning
sealers work well for this activity. Tape or staple the paper to form a
cylinder.
Devise a suspension system to hold the paper cylinder inside the jar,
1 cm above the bottom of the jar, without touching the sides of the jar.
Along the bottom of the paper cylinder, put dots from a variety of colours
of water-soluble markers. Keep the dots at least 2 cm from each other, each
3 cm from the bottom of the paper. Put water to a depth of 2 cm in the jar
so that the paper cylinder will be immersed about 1 cm in the water when
suspended. It is important that the water does not directly touch the dots.
Record the results. Why does the water soak upward through the paper?
What would happen if you used notebook paper or paper towel instead of coffee
filter paper? What would happen if you substituted a 1% salt solution for
the water in the jar. Use the knowledge gained from this investigation to
help solve one or both of the following mysteries.
Remove the nails and describe their appearance. Compare them to the third
nail which has been sitting on the desk beside the apparatus. What is the
experimental terminology used to describe the third nail? What chemical
reaction(s) took place during this activity? What evidence do you have that
the reaction(s) took place?
Tea, red cabbage juice, and turmeric are all acid/base indicators. Prepare
these substances in advance. Make a strong solution of orange pekoe or black
tea. (Herbal teas might be tried also to see if they are indicators as well.)
Shredded red cabbage with water in a 3:1 by volume ratio processed in a
blender produces a mash that can be filtered to yield juice to use in this
activity. Experiment with various strengths of aqueous turmeric solutions.
Combine the indicator with substances which are known to be acidic, neutral,
and basic. Record the colour of the indicator in each case. Keep these standard
samples for reference when other tests are made.
Have students bring in a variety of household substances to test. Some
examples include orange juice, grapefruit juice, lemon juice, apple juice,
vitamin C tablets, antacid tablets, ASA tablets, egg shells, hand soap,
baking powder, ammonia, ashes, laundry detergent, dish washing detergent,
cleansers, toothpaste, mouth wash, vinegar.
Make sure that students bring the samples in their original containers,
if it is practical to do so. Students should read the labels on the containers
to see if there are any warnings about how the material should be handled
or used. This is particularly important for any cleaners or detergents.
Compare the mixture of the indicator and the sample being tested with
a control sample of the indicator alone. Hold each up against a white surface,
or shine a light through each to assist in determining the relative colour.
The use of an overhead projector may be helpful in this regard.
After the results have been obtained, have students search for patterns
and generalizations. Have them develop operational definitions for acids
and bases.
Add a few drops of hydrogen peroxide to some of the filtrate. The solution
turns brown as ferric acetate is produced. (Use fresh hydrogen peroxide.
It is available in drug stores, and can be stored in a cool place for a
few weeks. Always handle peroxides with care.)
Add the ferric acetate to tea. Ferric tannate is produced. This is the
dye that was used in inks years ago. Use some of the dye to make drawings.
Another pigment that can be made is Prussian Blue. Dissolve some copper
(II) sulphate (also called bluestone and available in farm supply stores
or in Secondary Level chemistry labs) in water. Add ammonia. The solution
turns a deep blue colour.
Students investigate several chemical changes in this activity. Chemicals
have many uses. The production of dyes illustrates one practical application
of chemistry by the chemical industry.
Objectives: 1.1, 1.3, 1.4, 1.5, 3.2
Assessment Techniques: peer assessment, homework, written assignments
Instructional Methods: brainstorming, research projects
Objectives: 1.1, 1.4, 1.6, 3.2
Assessment Techniques: rating scales, presentations, peer assessments
Instructional Methods: research projects, reading for meaning
Code
Product
1
polyethylene terephthalate (PETE)
2
high density polyethylene (HDPE)
3
vinyl and polyvinylchloride (V)
4
low density polyethylene (LDPE)
5
polypropylene (PP)
6
polystyrene (PS)
7
other
Judging Sheet: Fantastic plastic Creations
"From monomers to polymers to you"
Group Name:
Product Name:
Creativity
(maximum 5 points)
Usefulness
(maximum 10 points)
Aesthetic appeal
(maximum 5 points)
Amount of waste produced
(maximum 10 points)
Advertisment
(maximum 5 points)
Creative name for product
(maximum 2 points)
Total points-