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Worksheet Grade 6 Health & Consumer Science

Larchmont's Water Report: A Grade 6 Percent-of-Limit Worksheet

A grade 6 consumer-science worksheet where students read a fictional town water report and find each test result as a percent of its legal limit.

Objectives

  1. Students will read a water quality report table and locate each measured value and its limit.
  2. Students will calculate each result as a percent of its legal limit and compare the results.

Vocabulary

Turbidity
Turbidity is a measure of how cloudy or murky water looks because of tiny particles floating in it. Clear water has low turbidity, and muddy water has high turbidity.

Also: chlorine, limit, percent

Teacher overview

Every year, a public water system mails its customers a water quality report that lists what was tested, the legal limit for each item, and the level the system actually measured. Reading that report is a real consumer skill. This worksheet gives students a short report from a fictional town and asks them to compare each result to its limit using percents, so a number like "0.12" turns into a clear idea of how far below the limit the town is running.

Larchmont's Water Report: A Grade 6 Percent-of-Limit Worksheet — Grade 6 Health & Consumer Science
Name: ____________________________ Date: ______________

Student Worksheet

Larchmont is a fictional town. Its yearly water report is shown below. Use it to answer the questions. To find a result as a percent of its limit, divide the result by the limit, then multiply by 100.

Test What it measures Limit or action level Larchmont result
Turbidity how cloudy the water is 0.3 NTU 0.12 NTU
Chlorine cleaning chemical left in the pipes 4.0 mg/L 1.1 mg/L
Lead metal from old pipes 15 ppb 3 ppb
  1. What does turbidity measure? Use the table.
  2. The turbidity limit is 0.3 NTU. Larchmont measured 0.12 NTU. What percent of the limit is that?
  3. The chlorine limit is 4.0 mg/L. Larchmont measured 1.1 mg/L. What percent of the limit is that?
  4. The lead action level is 15 ppb. Larchmont measured 3 ppb. What percent of the action level is that?
  5. Using your three percents, which result is the smallest share of its limit?
  6. A small amount of chlorine is left in the water on purpose. In one sentence, tell why.
  7. A neighbor says any chlorine at all means the water is unsafe. Use the report to explain why some chlorine is expected.
  8. Suppose Larchmont's lead rose to 6 ppb. What percent of the 15 ppb action level would that be?
  9. The lead action level will drop to 10 ppb in 2027. What percent of that new level is Larchmont's 3 ppb result?
  10. Every result is well below its limit. In one or two sentences, explain what that tells a customer.

From Water for Schools (waterforschools.org). This material is in the public domain (CC0) and may be copied, edited, and shared freely.

Answer Key
  1. Answer: How cloudy the water is. The table lists turbidity as a measure of cloudiness, which shows how clear or murky the water looks.
  2. Answer: 40 percent. 0.12 divided by 0.3 equals 0.40, and 0.40 times 100 is 40 percent of the turbidity limit.
  3. Answer: 27.5 percent. 1.1 divided by 4.0 equals 0.275, and 0.275 times 100 is 27.5 percent of the chlorine limit.
  4. Answer: 20 percent. 3 divided by 15 equals 0.20, and 0.20 times 100 is 20 percent of the lead action level.
  5. Answer: Lead. At 20 percent, lead is the smallest share of its limit, below turbidity at 40 percent and chlorine at 27.5 percent.
  6. Answer: To keep killing germs in the pipes. A little chlorine stays in the water so it keeps the water clean all the way to the tap.
  7. Answer: Some chlorine is expected because it protects the water on its way to homes. The report shows 1.1 mg/L, which is only 27.5 percent of the 4.0 mg/L limit, so the level is low and normal.
  8. Answer: 40 percent. 6 divided by 15 equals 0.40, and 0.40 times 100 is 40 percent of the 15 ppb action level.
  9. Answer: 30 percent. 3 divided by 10 equals 0.30, and 0.30 times 100 is 30 percent of the tighter 10 ppb level.
  10. Answer: It tells the customer the water met the rules with room to spare. Being well below every limit means the tested items were far under the levels the law allows. For lead, the action level is a trigger for the utility to act, not a safe level. EPA's health goal for lead is zero, so less is always better.

Differentiation

Support

Give students a worked first example (turbidity) with the division and the multiply-by-100 step already shown, and let them use a calculator. Provide a number line marked from 0 to 100 percent so they can place each answer and see how far below the limit the town runs.

Extension

Ask students to design a fourth row for the report with a made-up test, its limit, and a result, then write the percent-of-limit calculation that proves their result stays under the limit. Have them explain why a percent is easier to compare across tests than the raw numbers.

ELL supports

Provide a small picture glossary for "turbidity," "chlorine," "lead," and "limit," each with a simple sketch. Allow students to answer questions 1, 6, and 10 with short phrases or labeled drawings rather than full sentences.