Structures and Materials

Grade 3 Physical Science

Outcome: Assess properties of common materials and evaluate their suitability for use in constructing structures.

Indicator: Discuss the effects of obtaining materials from the environment (eg. cutting down trees, mining metals) and returning these materials to the environment after use (eg. lumber being sent to landfill, car rusting, plastic bags).

Objectives

• Students will be aware of the environmental impact everyday items they use have during manufacture and after use
• Students will be given tools to help make more environmentally sound choices in their everyday lives.

Lesson 1

Instructional Procedures:

1. Show the students a “mobius loop”.  (The recycling symbol with three arrows in a triangle) Ask students what they know about the symbol.  (It represents a closed loop for the recycling system.  As materials, such as paper, are manufactured, they enter the loop.  People use the paper and then, for the loop to continue, the paper must be recycled into a new product and people must choose to buy and use that product.)
2. Ask the students to name the 3Rs (Reduce, Reuse and Recycle).
3. Ask students to explain what recycling means. The idea is that in order for something to be truly recycled it must go through a change in state. For example, an aluminum can is melted down before it is formed into a new can.  
4. Recycling is important for a variety of reasons. 
1. It keeps materials out of the landfill.  Many materials put in the landfill break down slowly over time and chemicals leach from them into the earth and water.  These chemicals can be dangerous to both animals and humans.
2. It allows materials to be used again, instead of needing to harvest new materials each time.
3. Recycling materials takes less energy and resources than making the items from “virgin” material.
5. Everyone knows about recycling, but reducing and reusing are of equal value.  These options mean even fewer resources need to be harvested.
6. Have students brainstorm ways that they can reduce and reuse.  One way to reduce is to refuse. A person can refuse a plastic shopping bag by bringing their own, thus reducing the number of plastic bags being used. Can students think of other ways we can reduce? Reusing an item prolongs the life of the item, buying time before it is recycled or thrown away.  An example of reusing is using an empty chip tube to hold pens and pencils.
7. Have students make posters, depicting the 3Rs and their meanings.

Lesson 2

Instructional Procedures:

1. Review the 3Rs with the students.
2. The lesson will involve an investigation of aluminum drink cans.
3. Show the students an aluminum can and ask them what kind of material they think it is made of.  It is made from a specific metal called aluminum and a thin plastic lining.
4. Ask the students what they do with drink cans at their house, or when they are out, after they are empty.  Some people still do not realize that these containers can be returned for a refund at a SARCAN depot.
5. Fortunately in SK over 90% of drink cans are recycled.  Most of the un-recycled cans end up in a landfill and unfortunately they can also end up as litter. Drink cans in the landfill do not break down, taking up valuable land. 
6. Did you realize that we are charged an environmental fee for every drink can we buy?  Why do you think that the fee is charged? (It is to cover the costs of recycling the item, such as transportation).
7. We also pay a deposit on each container that we buy, which we get back when we return the cans to SARCAN.  (It is to encourage people to recycle the drink cans and continue the “recycling loop”.  Many people only recycle items to get the deposit back.)
8. What do the students think happens to the drink cans once they reach the recycling depot?  The aluminum is sent to a smelter and processed into huge rolls of aluminum that are used by many factories. Students may like to discover this on their own at http://www.sarcsarcan.ca/sarcan/wheredoesitgo/index.php.(See the Teacher Resource Sheet for a comparison of aluminum mining and aluminum recycling.)
9. How can we make a difference in our world concerning drink cans?  List the students’ ideas on the board or record the ideas in another high profile area. The best idea is to make sure their beverage containers are recycled, but students may have other ideas too.
10. When a person uses a drink can they make a decision – either they are going to recycle the can, helping continue the recycling loop or they are going to throw the can away, contributing to our landfills or litter. 

 Printable PDF version including teacher reference sheet

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