Birds build nests. The nests of barn swallows are quite different from those of the oriole, although both use mud as a major component. Owls and woodpeckers don't use mud at all. There are numerous ways to make a nest.
One of the questions which gives focus to the grade 7 curriculum is: How do we use specialized knowledge to meet our needs and suit our wishes? Humans construct all sorts of structures for a variety of purposes. Students here have an chance to examine the principles of construction and put their discoveries to use. Many structures or artifacts are designed to transmit or enhance the application of force. Structures must resist forces applied to them by wind, gravity, mechanical sources and other effects. Therefore, this unit could be integrated with the grade 7 unit Forces and Motion.
Science writing and reading activities, as discussed in this Guide, should be incorporated into each lesson. Through writing, students clarify their thoughts and understandings about the concepts they are considering. Through reading students can compare their ideas to the ideas of others and reconcile their view of the world with the scientist's view. Writing in personal, reflective journals, reading from newspapers and magazines, and reporting on the activities of science class in a variety of ways are only some ways 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.
One possibility of a science challenge activity is to hold a competition to build a structure of paper and white glue which will support a minimum mass of 500 g some arbitrary height (15 cm for example) above the surface of a table. Prizes or points could be awarded for greatest mass supported, mass supported to mass of structure ratio, innovative design elements, imaginative use of coloured paper for visual effect, tallest structure, completing project on time and within budget, minimum mass of paper and glue used to meet design criteria, and so on.
There is no single topic at the elementary level that is a direct precursor to this unit. Many life experiences have prepared students to consider the topics raised in this unit. Veins are the structural support for the photosynthetic tissue of the leaf. Stems are the structures which support the leaves so that they are exposed to the sun. Skeletons of both vertebrates and invertebrates give their bodies form and act as attachment sites for muscles. The physical properties of different types and states of matter are crucial when considering building materials.
This unit provides an excellent opportunity to consider some of the technological achievements which shape our society.
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: A2, A9, B16, C4, D3, F2, F5, G2
Objectives: 1.4, 3.2, 3.3, 4.5
Assessment Techniques: presentations, oral assessment, performance assessment
Instructional Methods: cooperative learning groups, concept formation
Factors: A2, B6, B7, B15, B24, C13, C14, D6, E6, F6, G7
Objectives: 1.2, 1.3, 2.1, 2.4,
4.3, 4.5
Assessment Techniques: self and peer assessments, observation checklists,
rating scales
Instructional Methods: compare and contrast, model building, problem
solving
Factors: A2, A9, B6, B15, B24, C13, D2, D6, F1, G2
Objectives: 1.2, 1.3, 2.1, 3.2,
4.4, 4.7
Assessment Techniques: group evaluations, anecdotal records, presentations
Instructional Methods: reflective discussion, model building
Activity 2 from the CEPUP unit on plastics, Plastics in Our Lives,
is a good one to use during this activity.
In Japan, water bags have been designed for this same use. What advantages
and disadvantages can you see in this innovation? Try to design a water
bag. Produce some water bags and sand bags and devise a test to compare
their effectiveness.
Carefully open the bag. Can you find more evidence about the way the bag
was sealed, and the way it was assembled originally? Is the bag made from
one piece or several pieces of material? Of what material is it made? Can
you make a model of the bag from paper or plastic? What other questions
about the bag are there to investigate?
Some one invented a machine which takes a piece of plastic, seals the
back and bottom seam, blows air into the empty bag, fills it with chips,
and then blows more air into it as the top is being sealed. Why would the
machine blow air into the bag at two different stages? Sketch the design
for a machine that could do this, keeping in mind your conclusions about
how the seams of the bag are sealed.
Obtain an empty cellophane tape dispenser. How closely does it match your
concept of what the dispenser was like? Carefully separate the dispenser
into 2 parts. How do the parts hold together when it is being used?
What type of process might be used to manufacture each part? Are they
carved from a block of solid plastic? Can you discover what kind of plastic
is used? What materials could be substituted for plastic in making a dispenser?
Give the advantages and disadvantages of each material.