Summary

In this activity, students will analyze a drinking water quality report from Washington, D.C. or from their city. Students will apply their knowledge of solutions and concentration in order to answer a series of questions using real-world data.

Grade Level

High School

NGSS Alignment

This activity will help prepare your students to meet the performance expectations in the following standards:

• HS-PS2-6: Communicate scientific and technical information about why the molecular-level structure is important in the functioning of designed materials.
• Scientific and Engineering Practices:
  • Analyzing and Interpreting Data
  • Engaging in Argument from Evidence

Objectives

By the end of this activity, students should be able to:

• Identify and distinguish between common units of measurement for concentration.
• Label the parts of a solution of tap water using the terms solute and solvent.
• Analyze the safety of local drinking water based on their understanding of concentration.
• Interpret data collected in comparison to acceptable standards.

Chemistry Topics

This activity supports students’ understanding of:

• Solutions
• Concentration
• Solute & Solvent

Time

Teacher Preparation: 10 minutes
Lesson: 30 minutes

Materials

• Classroom set of laptops (or printed copy of drinking water quality report)
• Drinking Water Quality Report from local jurisdiction
• 2023 Drinking Water Quality Report from Washington D.C. (optional)

Safety

• No specific safety precautions need to be observed for this activity.

Teacher Notes

• This activity can be used as an introduction to concentration or as a culminating activity at the end of a unit.
• Students should have an understanding of the terms solute and solvent prior to doing this activity. The AACT Solutions Animation is a good option to use before beginning this activity.
• A water quality report can be found for most cities on a local government webpage. For example, an annual water quality report for Washington, D.C. can be found at dcwater.org.
• If teachers prefer, use the 2023 Drinking Water Quality Report from Washington D.C. for this activity instead of a local report. Point students to pages 20-26.
• Next, give your students a brief overview of the sections in a water quality report. The page that gives the acronyms and the definitions of the different reporting measures used for concentration can be helpful (see page 21 of the 2023 Washington, D.C. report as an example). This is typically the page before water quality values are given. Additionally, using data as an example to compare “average” and “range” for contaminants could be helpful to review for student understanding.
• It is suggested that teachers review the student questions as a class at the end of the activity, encouraging students to share their answers. A class discussion can be useful to address possible misconceptions and discuss why students may have different answers to questions. For example, if students are just learning about concentration, they have a difficult time interpreting the difference between units “ppm” and “ppb”.
• An Answer Key document is provided for teacher reference.