All people make use of the principles of force and motion in most things we do. To get out of bed, to walk, to throw a ball, to remove a bottle cap from a bottle of pop - all require an application of force to produce a desired motion. The wrong amount of force or force improperly or carelessly applied results in a different effect than desired. In this unit, students will have opportunities to examine, measure, reflect upon, and discuss how forces of various origins are used to produce and control motion .
The heart of this unit should be in encouraging students to look for regularities or patterns in motion and in the forces which influence motion. To analyze what we often take for granted is a difficult but useful task. It requires that we look at things from a different perspective and consider what we may previously have overlooked.
Science writing and reading activities, as discussed in this Guide, should be incorporated into each lesson. Writing in personal, reflective journals, reading from both fiction and nonfiction, and reporting on the activities of science class by charts, cartoons, or plays are some strategies through which students may refine their understanding of the concepts of science and develop their ability to communicate through the written word.
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. 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.
A challenge activity relevant to this unit might be designing a paper airplane which will stay aloft a maximum amount of time, or building some sort of Rube Goldberg device using a variety of simple machines to transfer force in order to accomplish a task.
Note: Many of the resources listed in Science:
An Information Bulletin for the Middle Level - Key Resource
Correlations describe activities or ideas for activities.
Where is the force applied? Where does the critical (intended) motion take place?
Factors: B7, B10, C8, C9, C15, D3, F2, F7
Objectives: 1.1, 1.3, 2.1, 4.1, 4.2, 5.3
Assessment Techniques: observation checklists, presentations, self-assessment
Instructional Methods: inquiry, conducting experiments, discussion with peers
Objectives: 1.3, 4.2,
4.3, 5.3
Assessment Techniques: self-assessments, anecdotal
records, written assignments
Instructional Methods: reflective discussion,
conducting experiments
What happens to the motion when they blow harder? What
happens if a cut is made lengthwise from the free end about
halfway up to the end near the lip? What happens when the
strip is folded across the short dimension so that there is
a flap about 3 cm long sticking up at the free end? What
happens when the end is held on the top lip and the stream
of air is directed under the strip?
Further investigations of the forces related to lift and
flying can be found in the book Super Flyers
(Francis, 1988). This book is an excellent collection of
activities and is protected by copyright. Sufficient copies
should be purchased so that each student or group has easy
access to a copy while it is being used. Depending on how
the class is organized, one copy for every three to ten
students should be adequate.
Factors: B5, B9, B20,
C11, C16, D3,
G3
Assessment Techniques: contracts, rating scales,
short answer test items
Instructional Methods: reflective discussion, model
building, learning centres
What starts a pendulum moving? What keeps a pendulum
moving?
What determines the direction it moves? Does the string
stay
in a straight line as it moves or does it curve? How about
if paper clips are used instead of string to support the
bob? How many uses of pendulums can you list?
What is the purpose of the string? of the straw? What
happens when a balloon is inflated and released without
being attached to the fish line by the straw? Why does the
balloon take the path it does? Why doesn't the rocket
carrying the space shuttle travel in a path similar to a
balloon? Does it have a fish line to outer space to travel
on? Can you devise a ballon rocket that will fly straight
without a line to guide it?
Extension: How does the speed of the wind influence the
energy output of the windmill? Create a device to measure
this relationship. Is the relationship linear?
While the card is flat on the table, label one of the arms
#1 and the other #2, as in the diagram below. Along the line
where the arms join the base fold the arms in opposite
directions so that they are perpendicular to the plane of
the base. The number on one arm will now be facing up and
the other number will be facing down. Note which number is up.
Holding the card with the base down at arm's reach above
the
head, drop the card and observe its fall. Add a paper clip
to the centre of the base and repeat. Keep adding paper
clips, dropping, and recording observations until five
clips
are attached to the base. What generalization can you make
about the effect of paper clips on the fall of the card?
Drop the card again. In which direction does it rotate?
Does
it always rotate the same direction every time you drop it?
Compare your direction of rotation with the direction of
rotation other groups have found.
Change the direction the arms are folded so that the number
which was previously up is now down, and vice versa. Drop
the card and note the direction of rotation. Discuss your
observations with other groups and create a general
statement which can be used to predict how any unlabelled
card of this type will rotate.
As a class brainstorm a list of variables which can be
tested to determine their effect on the fall of the card.
Divide these variables for investigation among the groups
in
the class.
