Lesson 15Using Water Efficiently
Learning Goal
Let’s investigate saving water.
Learning Targets
I can answer a question by representing a situation using proportional relationships.
Warm Up: Comparing Baths and Showers
Problem 1
Some people say that it uses more water to take a bath than a shower. Others disagree.
What information would you collect in order to answer the question?
Estimate some reasonable values for the things you suggest.
Activity 1: Saving Water: Bath or Shower?
Problem 1
Describe a method for comparing the water usage for a bath and a shower.
Find out values for the measurements needed to use the method you described. You may ask your teacher or research them yourself.
Under what conditions does a bath use more water? Under what conditions does a shower use more water?
Activity 2: Representing Water Usage
Problem 1
Continue considering the problem from the previous activity. Name two quantities that are in a proportional relationship. Explain how you know they are in a proportional relationship.
Problem 2
What are two constants of proportionality for the proportional relationship? What do they tell us about the situation?
Problem 3
On graph paper, create a graph that shows how the two quantities are related. Make sure to label the axes.
Problem 4
Write two equations that relate the quantities in your graph. Make sure to record what each variable represents.