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# Bottled Water

## What’s the best size of disposable water bottle?

What’s the best size of disposable water bottle? Bottled water is one of the best-selling drinks on Earth. While disposable bottles offer a convenient way to stay hydrated, they also require a lot of plastic that can be harmful to the environment.

In this lesson, students use the volume and surface area of cylinders to compare disposable water bottles and consider environmentally-friendly ways to stay hydrated.

### REAL WORLD TAKEAWAYS

• Millions of tons of single-use plastic water bottles have ended up in the oceans and are wreaking havoc on wildlife
• Our daily consumption habits, like what size and material water bottle to use, affect the well-being of the planet and a host of creatures living on it.
• We can slow the flow of plastics into the oceans when we: (1) reduce, (2) reuse, (3) recycle, (4) repair, (5) rethink, (6) refuse.

### MATH OBJECTIVES

• Use the formulas for volume of a cylinder and volume of a sphere to solve real-world problems.
• Model with geometry.
• Reason about the surface area of a real-world object. (No formulas required.)

Appropriate most times as students are developing conceptual understanding.