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Lesson plan Grade 6 Health & Consumer Science

Lead at the Whitfield Tap: A Grade 6 Home Water Safety Lesson

A grade 6 health lesson where students read a fictional home lead-test table, compute each result as a percent of the action level, and learn a safe tap habit.

Objectives

  1. Students will express a measured lead level as a percent of the federal action level.
  2. Students will explain a home habit that lowers the amount of lead in tap water.

Vocabulary

Lead (Pb)
A soft gray metal that is poisonous, especially for children. It can get into drinking water from old pipes and plumbing, so utilities work hard to control it.
Action level
A trigger number in lead and copper testing. If too many homes test above this level, the utility must take steps like improving treatment and telling the public.

Also: parts per billion, flushing

Teacher overview

Lead can enter tap water from older pipes and fixtures, and it has no color, taste, or smell, so the only way to know a home's level is to test the water. This lesson uses fictional test results from the Whitfield family's kitchen tap to teach two things at once: how to read a lead-results table against the federal action level, and a simple habit that lowers lead at the tap. Students compute each result as a percent of the action level, which is the number that triggers a utility to act, not a line between safe and unsafe. A common misconception this lesson corrects is that clear water must be lead-free; clarity says nothing about lead.

The federal action level is 15 parts per billion, and it is set to drop to 10 parts per billion in 2027, so the same test result counts as a larger share of a lower action level.

Procedure

Hook (5 min): Pour a glass of clear water and ask whether students can tell if it contains lead. Establish that they cannot, because lead is invisible and has no taste, which is why testing matters.

Read the table and direct instruction (12 min): Project the fictional Whitfield results and read them with the class.

Sample Lead measured (ppb)
First draw, water sat in the pipes overnight 9
After running the cold tap for 2 minutes 2

Explain that the first draw sat in contact with the pipes all night, so it picked up more lead, while running the tap first flushes that water out. Define the action level of 15 ppb as the level at which a water system must take action, and stress that lower is always better. Post the five numbered questions students will work during the lesson:

  1. The first-draw sample measured 9 ppb. What percent of the 15 ppb action level is that?
  2. Using the lower 10 ppb action level that takes effect in 2027, what percent of that lower action level is the same 9 ppb first-draw result?
  3. The flushed sample measured 2 ppb. What percent of the 15 ppb action level is that?
  4. Which of the two measured samples would you rather drink, and why?
  5. A different tap tests at 6 ppb. What percent of the 15 ppb action level is that?

Worked example, questions 1 and 2 (8 min): Model the percent method with the class: to find what percent of the action level a result is, divide the result by the action level. Work question 1: the first-draw result of 9 ppb, as a percent of the 15 ppb action level, is 9 divided by 15, which equals 0.60, or 60 percent. Then work question 2 against the lower future action level: 9 divided by 10 equals 0.90, or 90 percent of the 10 ppb level that takes effect in 2027.

Guided practice, questions 3 and 4 (13 min): In pairs, students answer question 3, finding the flushed result of 2 ppb as a percent of the 15 ppb action level, and question 4, deciding which of the two samples they would rather drink and why. Circulate and confirm pairs divide by the action level rather than by 100.

Safe-habit practice and discussion (7 min): As a class, list steps that lower lead exposure at home: run the cold tap before drinking after water has sat, use cold water for drinking and cooking because hot water dissolves more lead, and use a filter certified to remove lead. Have students explain why the flushed sample had a lower number.

Closure and exit ticket, question 5 (5 min): Students answer question 5 individually: a tap tests at 6 ppb; what percent of the 15 ppb action level is that? Collect and scan for the correct division.

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: 60 percent. Question 1, the first-draw sample: 9 ppb divided by the 15 ppb action level equals 0.60.
  2. Answer: 90 percent. Question 2, the same first draw against the future action level: 9 ppb divided by the 10 ppb level equals 0.90.
  3. Answer: about 13 percent. Question 3, the flushed sample: 2 ppb divided by 15 ppb equals about 0.13, so running the tap first sharply lowered the share of the action level.
  4. Answer: The flushed sample. Question 4: it measured 2 ppb versus 9 ppb, so students should prefer the water drawn after the tap ran, because it held far less lead.
  5. Answer: 40 percent. Question 5, the exit ticket: 6 ppb divided by the 15 ppb action level equals 0.40.

Differentiation

Support

Provide the division set up as a fraction with the action level already in the denominator, and let students use a calculator. Give a labeled picture of water sitting in a pipe overnight versus fresh water flushed through, so the reason for the two results is concrete.

Extension

Ask students to explain, in a short paragraph, why the same 9 ppb result becomes a larger percent when the action level drops from 15 to 10 ppb in 2027, and what that change means for households that only flush sometimes.

ELL supports

Pre-teach "lead," "action level," and "flush" with images: an old pipe, a scale with a marked line, and a tap running water down the drain. Provide a sentence frame: "The water measured ___ ppb, which is ___ percent of the action level."