Last updated: July 22, 2020

*Math Skill: Interpreting bar graphs *

Science Subject: Protection of Earth’s resources

*Grade level: Grade level: 4th – 5th grades*

*Area level: National-scale*

*Environmental Area: Energy*

*Purpose: Understand that it takes much less energy to produce aluminum cans from recycled aluminum than virgin ores and develop awareness of recycling*

### BACKGROUND FOR THE TEACHER

It is suggested to recycle aluminum cans after usingthem. Why? It is because recycling aluminum is beneficial. One of the advantages of recycling aluminum is that production of aluminum from recycled aluminum requires only 8% of the energy than production from virgin ore. Manufacturers can also reuse aluminum repeatedly without losing quality. Aluminum cans now contain 70% recycled content on average.

In2018alone, the industry recycled 56.2 billioncans (63.6%) in our nation. (The Aluminum Association). However,at the same time,35.2 billion cans were not recycled and ended up in landfills in 2018.Energy saved by recycling all aluminum cans is equivalent of powering 4.1 million homes for a full year. Recycling aluminum also saves our natural resources from being depleted and reduces emissions of carbon dioxide.

#### Environmental impacts from municipal solid waste (MSW) & What we candy

### TEACHER GUIDE

The purpose of this activity is to enhance students’ skills in interpreting bar graphs. Using the bar graph on how much energy is required to produce 1 kg of aluminum from recycled aluminum and virgin ore, this activity provides 2 worksheets. To make it easier for students to understand the mass, 1kg of albumin is expressed as 70 aluminum beverage cans.* Problem A asks basic questions about what the bar graph is trying to show , while Problem B asks more complicated questions that require multiplication and division skills. The problems were created based on data obtained from Low-Tech Magazine.

* A 330 ml aluminum can weighs about 13 grams (International Aluminum Institute). Electricity price was used here is 6.4 cents (the national average of Industrial electricity prices in April 2020) (EIA)

### worksheet & answer key

#### TYPE A

*Math Skill: Interpreting bar graphs *

Using the bar graph on how much energy is required to produce 70 aluminum beverage cans from recycled aluminum and virgin ore, students are asked to find out what the graph is trying to show.

#### TYPE B

*Math Skill: Interpreting bar graphs *

Using the bar graph on how much energy is required to produce 70 aluminum beverage cans from recycled aluminum and virgin ore, students are asked to interpret the bar graph by using multiplication and division skills.