Worksheet Grade 6 Health & Consumer Science

Emberly's Well Test for PFAS: A Grade 6 Parts-per-Trillion Worksheet

A grade 6 worksheet where students read a fictional well's PFAS test, find each result as a percent of the limit, and decide which chemical is over the limit.

Grade: Grade 6
Subject: Health & Consumer Science
Material: Worksheet
Time: 40 min
Prep: No prep
Materials: None

Standards

6.RP.A.3 Common Core Math

Use ratio and rate reasoning to solve real-world and mathematical problems, e.g., by reasoning about tables of equivalent ratios, tape diagrams, double number line diagrams, or equations, including finding a percent of a quantity and converting measurement units.

How this material aligns: Students divide each PFAS result by the 4.0 ppt limit to find a percent of a quantity and figure how far a result runs over the limit, the percent work 6.RP.A.3 requires.

All materials for 6.RP.A.3 →

RST.6-8.7 Common Core ELA

Integrate quantitative or technical information expressed in words in a text with a version of that information expressed visually (e.g., in a flowchart, diagram, model, graph, or table).

How this material aligns: Students read the well-test table and match each chemical's measured value to the written questions, integrating the quantitative table with the text as RST.6-8.7 requires.

All materials for RST.6-8.7 →

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This material is in the public domain (CC0) and may be copied, edited, and shared freely, without attribution. Updated 2026-07-17.

Objectives

Students will read a PFAS test table and find each result as a percent of its legal limit.
Students will decide which result is over the limit and by what percent it exceeds it.

Vocabulary

PFAS: A large family of human-made chemicals used in things like nonstick pans, waterproof fabric, and firefighting foam. They are called forever chemicals because they take a very long time to break down.
Parts per trillion: A unit for measuring extremely small amounts of a chemical in water. PFAS limits are set in parts per trillion because these chemicals matter even in tiny doses.

Also: limit, percent

Teacher overview

PFAS are a group of human-made chemicals used in many products, and they can end up in water. Because they have no color, taste, or smell, a well has to be tested to know if PFAS are present. The federal limit for two common PFAS, called PFOA and PFOS, is 4.0 parts per trillion each, though the compliance timeline for that 2024 rule is still being finalized. This worksheet gives students a fictional well test and asks them to compare each result to the limit with percents, the same reasoning a family or town uses to decide whether to add treatment.

Emberly's Well Test for PFAS: A Grade 6 Parts-per-Trillion Worksheet — Grade 6 Health & Consumer Science

Name: ____________________________ Date: ______________

Student Worksheet

Emberly is a fictional town. PFAS are a group of human-made chemicals used in many products. They have no color, taste, or smell, so a lab test is the only way to find them. Emberly tested one well for PFAS. The results are below. To find a result as a percent of the limit, divide the result by the limit, then multiply by 100.

Chemical	Legal limit	Emberly result
PFOA	4.0 ppt	2 ppt
PFOS	4.0 ppt	5 ppt

What are PFAS? Use the note above the table.
The limit for PFOA is 4.0 ppt. Emberly measured 2 ppt. What percent of the limit is that?
The limit for PFOS is 4.0 ppt. Emberly measured 5 ppt. What percent of the limit is that?
Which chemical is over its limit?
By what percent does that chemical go over its limit?
Which chemical is exactly at half of its limit?
To reach the limit, how many ppt must the PFOS result drop?
Suppose a filter cuts the PFOS result in half. What would the 5 ppt result become, and is that under the limit?
After the filter, what percent of the 4.0 ppt limit is the new PFOS result?
Water from this well looks and tastes fine. In one or two sentences, explain why testing still matters.

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

Answer Key

Answer: A group of human-made chemicals. PFAS are human-made chemicals used in many products, and they can get into water without changing how it looks or tastes.
Answer: 50 percent. 2 divided by 4.0 equals 0.50, and 0.50 times 100 is 50 percent of the PFOA limit.
Answer: 125 percent. 5 divided by 4.0 equals 1.25, and 1.25 times 100 is 125 percent of the PFOS limit.
Answer: PFOS. Its result of 5 ppt is above the 4.0 ppt limit, while PFOA at 2 ppt is below its limit.
Answer: 25 percent. PFOS is at 125 percent of the limit, which is 25 percent over the 100 percent line.
Answer: PFOA. Its result of 2 ppt is exactly half of the 4.0 ppt limit, or 50 percent.
Answer: 1 ppt. The 5 ppt PFOS result minus the 4.0 ppt limit equals 1 ppt that must be removed to reach the limit.
Answer: 2.5 ppt. Half of 5 ppt is 2.5 ppt, which is under the 4.0 ppt limit, so the filter would bring the well under the limit.
Answer: 62.5 percent. 2.5 divided by 4.0 equals 0.625, and 0.625 times 100 is 62.5 percent of the limit.
Answer: Testing still matters because PFAS have no color, taste, or smell, so the only way to know they are present is a lab test, no matter how clean the water looks.

Differentiation

Support

Give a worked first example (PFOA) with the division and the multiply-by-100 step shown, and let students use a calculator. Provide a 0-to-125 percent number line so students can mark each result and see which one crosses the 100 percent limit line.

Extension

Ask students to find how much a filter would need to cut the PFOS result, as a percent, to bring it exactly to the 4.0 ppt limit rather than below it, and to explain why a town might aim well under the limit instead of right at it.

ELL supports

Pre-teach "PFAS," "limit," and "over the limit" with a simple bar picture showing a result above and below a marked line. Allow students to answer questions 1 and 10 with short phrases or a labeled drawing rather than full sentences.