LESSON 4
Honey, I Shrunk the Lids!


HANDOUTS:	Weight Reduction Continues With "202" Ends (PDF 14KB) Fun Facts on Can History Fun Facts on Aluminum Can Recycling

SUBJECT AREAS:	Science, Language Arts, Math

TEACHING OBJECTIVE:	To introduce the concept of lightweighting by the manufacturer.

SKILLS:	Observation, Research, Reporting

MATERIALS:	can ends of different sizes (Call 1-888-Can-Central to order free of charge) empty aluminum cans copies of handout "Weight Reduction Continues with '202' and '204' Ends" copies of "Fun Facts" fact sheets

KEY VOCABULARY:	lightweighting renewable resources nonrenewable resources

TEACHER TIP:	Remind students of concepts from Lesson 3 about the life cycle of an aluminum can and how each can is made from two pieces of aluminum. You may want to make the clay models students constructed in Lesson 3 available for reference.

TIME:	Preparation Gather empty aluminum cans or have students bring them in, 5 minutes Make copies of handout "Weight Reduction Continues with '202' and '204' Ends," 5 minutes Make copies of "Fun Facts" fact sheets, 5 minutes Class Time 45 minutes

BACKGROUND

Since 1972, the aluminum industry has reduced the amount of aluminum needed to make each aluminum can by almost one-third. The can manufacturing industry, by consistently reducing the amount of material used to make each can, including creating new beverage can designs, advances the concept of lightweighting — the process of producing the same quality can with less material to conserve aluminum resources.

In 1972, one pound of aluminum yielded only 21.75 cans. Today, by using less material to make each can, one pound of aluminum makes approximately 32 cans — a 47 percent improvement. Even the can ends have gotten lighter. The old ends weighed about 8.12 pounds per thousand. Now they weigh a mere 6.07 pounds per thousand. It may not seem like much, but when you multiply the savings by the 100 billion cans that are made each year, the weight savings is
phenomenal — over 200 million pounds of aluminum!

PROCEDURE

1. Make sure each student or group has an empty aluminum can. Review the concept of cycles by showing the two examples of aluminum can cycles on the chalkboard or flipchart, one "incomplete," the other a "closed loop." Ask students to tell the consequences of each cycle.

2. Note that bauxite ore, and therefore aluminum, is a nonrenewable resource (if needed, ask students to recall the definition of nonrenewable). Remind students of earlier lessons in which they suggested alternatives to using up resources (use them again, use less material to make the same package, recycle). Explain that the aluminum and can industries have found ways to produce aluminum cans so that resources are conserved rather than used up.

3. Show students the can ends (Call 1-888-Can-Central to order free of charge), explaining that the #206 was an early design, the #204 came later, and now we have the #202. Ask students to tell you what they notice about the size of the can ends (they are getting progressively smaller). Tell the students that 1,000 #206 ends weigh 8.12 pounds; 1,000 #204 ends weigh 6.67 pounds; 1,000 #202 ends weigh 6.07 pounds. Ask them why they think this is so (making them smaller means making them lighter and using less aluminum).

4. Pass out the handouts "Weight Reduction Continues with '204' and '202' Ends." Explain that this process of conserving resources is called "lightweighting." Ask students to match their can ends to the diagrams on the handouts. What sizes are their can ends?

5. Inform the students that the aluminum and can industries have also conserved resources by using recycled aluminum to make other aluminum products. Each "new" can uses an average of 54 percent recycled aluminum, thereby using less source material (lightweighting).

6. Have students break into groups to discover and report on other facts about aluminum and aluminum can recycling. Distribute different copies of the "Fun Facts" handouts to each group and see how many facts they can discover in 10 minutes. Then have each group report its findings to the class.

WRAP UP

(Students can choose one of the following activities.)
1. Imagine you were working for the aluminum industry when the discoveries about how to conserve aluminum by lightweighting were made. Write a news article about your company's discovery for a local newspaper. Remember to include who, what, when, where, why and how. Stories should also include what this means for the environment. Read your story to the class.

2. Use the words renewable, nonrenewable, bauxite ore and lightweighting in sentences that show their meaning.

EXTENSION

1. Can students suggest further modifications to the aluminum can manufacturing process to maximize the lightweighting concept? (e.g., changing standard number of ounces per can to make smaller servings) How would they "sell" this to consumers? Create an advertisement for the new features of the can.