Environmental data lab
Open your materials, follow the steps, then turn in your work.
Measure the lowest contaminant concentration your water test can actually detect, then decide whether a test that sensitive could enforce a real drinking-water limit.
1. Open your materials
Use the materials named in the first step below. Open lesson resources.
2. Start the work
Write the claim you are testing: below some concentration this test reads negative even though the starch is still in the tube. Predict which tube that will be.
Show all 7 required steps
- Write the claim you are testing: below some concentration this test reads negative even though the starch is still in the tube. Predict which tube that will be.
- Label eight tubes before anything goes in them: B for the blank, S0 for undiluted stock, S1 through S5 for the dilution series, and U for the coded unknown.
- Put 10 mL of distilled water in B, 10 mL of undiluted starch stock in S0, and 9 mL of distilled water in S1 through S5.
- Build the 1:10 series. Carry 1 mL of stock into S1 and mix, carry 1 mL of S1 into S2 and mix, and keep going through S5. Change the pipette tip at every single step.
- Add two drops of Lugol's iodine to all eight tubes, including B and S0, then start a 60 second timer.
- Read every tube against the same white background and record it as positive (blue-black) or negative (the same yellow-brown as the blank).
- Name your detection limit, run the coded unknown the same way, and compare your limit to the EPA drinking-water limit you were assigned.
Lost your place? Lost your place? Open the air or water dataset, find the concentration column and its units, compare to the published safe threshold, then estimate dose from concentration and assumed intake. Flag anything that looks like it builds up over time.
Check your work before submitting
- You can state the lowest concentration your test detected and point at the tube that proves it.
- You can name your independent variable, your dependent variable, and what each of your two controls rules out.
- You can explain why a negative tube does not mean the water is clean.
Before lab work: read the safety rules
- Lugol's iodine stains skin and clothing permanently and irritates the eyes. Goggles, nitrile gloves, and a lab apron go on before the bottle is opened, and the bottle is capped between uses.
- Iodine is harmful if swallowed. Nothing goes in your mouth, never pipette by mouth, and no food or drink is on the bench today.
- Iodine on skin: wash with soap and running water for at least 15 minutes. Iodine in an eye: hold the eye open at the eyewash for at least 15 minutes and tell Mr. Mendoza while you are still rinsing.
- Spill on the bench: keep gloves on, absorb with paper towels working from the outside of the spill inward, put those towels in the chemical waste container, then wipe with water.
- Never pour iodine waste into the bleach container or any other waste stream. Bleach oxidizes the iodide in Lugol's and drives off iodine vapor, and combining waste streams is how a classroom ends up breathing a gas nobody planned for.
- All iodine-containing liquid goes into the labeled chemical waste container for disposal per the SDS. Nothing from this lab goes down the sink.
- Report a chipped or cracked tube before you fill it. Broken glass goes into the labeled broken-glass container, not the regular trash.
- The starch stock is a laboratory reagent, not food. Do not taste any tube, including the blank.
- Change the pipette tip at every dilution step. A reused tip carries starch forward and manufactures a false positive at the low end, which is a data problem, not a safety one, but it ruins the run either way.
- Gloves come off last, then wash your hands with soap and water for 20 seconds before you leave the room.
3. Turn in your work
DueCheck Schoology- Hand in
- Detection-limit data table: the claim you predicted, the concentration of every tube in the series, the color call for each, the positive and negative control results named as such, the detection limit stated with units, the coded unknown result, one sentence comparing your detection limit to the assigned EPA drinking-water limit, and one named limitation of reading this test by eye.
How to submit and name your file
Use the submission route shown on today's today's page.
In Schoology, open your course and the assignment for this lesson. Attach your file, select Submit, and check that it appears in the submission.
PDF upload helpYou get two school days for every day you were absent, so this deadline moves with you.
How this lesson connects
Keep using what you learned last class: Pollution sources were sited by past decisions, so environmental health burdens fall harder on lower-income and marginalized neighborhoods, and exposure data reveals that uneven pattern. Today: A concentration only becomes a health risk once intake and body weight turn it into a dose, so you compare dose (not concentration) to the safe threshold, and bioaccumulation can push a safe-looking level into a dangerous one over time.
Optional: listen or watch a unit review▸
Need help? Warm-up, timing, and directions▸
💡 Big idea: A concentration only becomes a health risk once intake and body weight turn it into a dose, so you compare dose (not concentration) to the safe threshold, and can push a safe-looking level into a dangerous one over time.
- 0-10 min briefing: iodine PPE, the chemical waste container, and where the eyewash is. Goggles, gloves, and apron on before any bottle opens
- 10-25 minLabel all eight tubes, load the water volumes, and build the 1:10 series from the starch stock, changing the tip at every step
- 25-40 minAdd two drops of Lugol's iodine to all eight tubes including B and S0, run the 60 second timer, and read against a white background
- 40-55 minRecord positive or negative for every tube, name your detection limit, and run the coded unknown
- 55-70 minCompare your detection limit to your assigned EPA drinking-water limit and write whether this test could enforce it
- 70-80 minRoute all iodine waste to the chemical waste container, wipe the bench, wash hands, and submit your
- • Every water test ever run has a floor, and today you find the floor of yours using starch as a safe stand-in for a pollutant.
- • You will build a ten-fold dilution series, develop every tube with iodine, and read the tube where the color quits.
- • The tube where the color quits is not the tube where the starch quits. That gap is the entire lesson.
- • At the end you hold your floor next to a real EPA drinking-water limit and say whether this test could enforce it.
- • A builds a set of known concentrations by repeating the same , so each 1:10 step is ten times weaker than the one before it.
- • The detection limit is the lowest concentration a method still calls positive; below that concentration the method returns a even though the substance is there.
- • Two controls run beside the series. Tube S0, the undiluted stock, is the and proves the iodine is working; tube B, distilled water plus iodine, is the and proves nothing carried over on a tip.
- • The is starch concentration and the is the color call, so a result you cannot tie back to a labeled tube is not data.
- • Starch is a safe stand-in, not a pollutant. Today measures what this method can do, so nothing you find here says anything about whether real water is safe to drink.
PLTW connection and today's work
Open Problem 4 Investigating Environmental Health in your myPLTW course shell and navigate to the current water-testing activity, then run the detection-limit series and record a raw color call for every tube.
Today's stopping point: The environmental justice debate is done; this is the mid-Problem 4 bench milestone, so check your activity guide and confirm your raw data is recorded before cleanup starts.
PLTW activity titles identify the course connection. If your account will not open, use the posted materials for today and tell Mr. Mendoza. Do not mark an online activity complete unless you completed it.
Course connection
- Activity 4.1.1 Environmental Exposures
Use the turn-in directions at the top of this page. Do not create a second submission unless your teacher asks for one.
Show another explanation or a smaller first step
Need help? Choose a starting point
Finish the assigned lab safely before starting extra practice.
Lesson resources: reading, slides, and vocabulary▸
The deck carries the prior idea forward, lets you inspect an analogy, maps the rule to biology, and ends with the same evidence decision and exit ticket used on this page.
Generated from this lesson's canonical data with a red-team citation check.
Pollution sources were sited by past decisions, so environmental health burdens fall harder on lower-income and marginalized neighborhoods, and exposure data reveals that uneven pattern.
A concentration only becomes a health risk once intake and body weight turn it into a dose, so you compare dose (not concentration) to the safe threshold, and can push a safe-looking level into a dangerous one over time.
A research team lays out its question, variables, controls, sampling plan, measurement record, and analysis before deciding what the data support.
- Which variable is changed or compared?
- Which conditions and measurements must stay consistent?
- Which conclusion is inside the study's evidence boundary?
Define variables, controls, sampling, units, and the analysis plan before interpreting a result; analysis cannot repair biased or inconsistent measurement.
A well-organized classroom study can still be limited by , measurement quality, confounding, and the population represented.
- • Question and variable cards map to the study design.
- • Control and measurement cards map to fair, reproducible data collection.
- • The conclusion card maps to a bounded claim supported by the analysis.
Driving question: The dataset lists a pollutant concentration in the air or water, but a number with units is not yet a risk, so how do you turn a concentration into a dose a body actually receives and decide whether that crosses the safe line?
What you already know: Pollution sources were sited by past decisions, so environmental health burdens fall harder on lower-income and marginalized neighborhoods, and exposure data reveals that uneven pattern.
New idea: A concentration only becomes a health risk once intake and body weight turn it into a dose, so you compare dose (not concentration) to the safe threshold, and can push a safe-looking level into a dangerous one over time.
Visual or model: F1. F1. A lesson illustration or teaching diagram for Environmental data lab. Use it with E1-E3; it is a model or context image, not experimental or patient data. What to notice: Trace the labeled system, test, or design relationship and identify which evidence should trigger revision.
- Observe or measure the relevant feature in environmental data lab.
- Organize the observation with a stable evidence ID.
- Apply this rule: Define variables, controls, sampling, units, and the analysis plan before interpreting a result; analysis cannot repair biased or inconsistent measurement.
- Choose the option the evidence supports and state the limit of the conclusion.
Real biomedical example: An environmental-health claim is defensible only when the graph, comparison, and limitation are cited directly in the reasoning. Source: Khan Academy: Correlation and causality.
What the evidence supports: E1-E3 and F1 support the daily take-home when the response meets the stated success criteria.
What it cannot prove: The package does not support claims beyond this lesson's or any real patient diagnosis.
- • : A poisonous substance produced by a living organism, such as bacteria, plants, or animals, that can damage cells or disrupt body functions.
- • exposure: Contact with a substance, agent, or condition that could affect health, such as a chemical, , or environmental factor.
- • dose: The measured amount of a drug or substance given at one time, chosen to be effective while staying safe for the patient.
- • pollutant: A harmful substance released into air, water, or soil that can damage ecosystems and human health.
- • : The gradual buildup of a substance, such as a , inside an organism faster than the body can break it down or remove it.
- • risk: The chance that a harmful event, such as getting a disease, will happen within a given group or time period.
Use it now: Choose one decision option. Cite E1 and E3, then explain how the rule connects the evidence to your choice.
Go further, optional: The source links below are optional enrichment. Every fact required for today's local evidence decision appears in this lesson package.
Environmental health risk is characterized by integrating hazard, dose-response, exposure, and uncertainty; an observed association or model result does not by itself establish individual causation.
Limit: A classroom dataset cannot represent every exposure route, susceptible group, confounder, or long-term outcome.
Define variables, controls, sampling, units, and the analysis plan before interpreting a result; analysis cannot repair biased or inconsistent measurement.
Limit: A well-organized classroom study can still be limited by , measurement quality, confounding, and the population represented.
You can state the lowest concentration your test detected and point at the tube that proves it.
Limit: E3 defines the classroom product or success criterion. It is not independent scientific evidence and cannot justify a clinical or causal claim.
PLTW-BFH-2027-04-08 · Simulated classroom evidence scenario
Your role: biomedical design team member
Decision: Your team must decide what the evidence from environmental data lab supports before submitting the labeled and result claim named on today's page.
- • Find how long people are exposed before judging risk, because a substance that builds up changes a safe-looking dose.
- • Turn the concentration into a dose using intake and body weight, then compare that dose to the threshold.
- • Report the water as safe, since the listed concentration sits below the published limit for that pollutant in the dataset.
Response: State one choice, cite at least two evidence IDs, explain the rule that connects them, and add one limitation. Submit it as the labeled and result claim.
Claim ceiling: Today's evidence supports a classroom claim about environmental data lab. It cannot prove causation, diagnose a real patient, or justify action outside this room.
= final volume / sample volume. New concentration = starting concentration / dilution factor.
Mix 1 mL of sample to a final volume of 10 mL. The is 10. A 100 mg/mL starting sample becomes 10 mg/mL.
Use the same volume units before dividing. Concentration keeps its original concentration unit.
Apply the same setup to one supplied dilution or dose. Show the factor, new value, units, and a reasonableness check.
- • The solution must address the stated need in environmental data lab.
- • The decision must be supported by E1-E3.
- • The final product must make the success criteria visible.
- • Complete the work inside the 80-minute block.
- • Use only supplied or teacher-approved materials and evidence.
- • Do not trade , accessibility, or privacy for speed.
- • and evidence quality: must pass before scoring other criteria.
- • User need and effectiveness: highest scored criterion.
- • Time, cost, and ease of use: compare only after and effectiveness pass.
Test evidence: For each option, record the E1-E3 result that supports or fails each criterion. Do not assign a score without a named observation.
- Version or option tested
- Criterion met or missed
- Evidence ID and result
- Revision made
- Reason for the revision
- Need and user
- Criteria and constraints
- Chosen option and evidence
- Test result
- Revision and reason
Students often think Students often treat concentration and dose as the same thing, assuming that if a level is 'below the limit' the water or air is automatically safe for everyone.. The trap: Concentration times how much you take in times how long is what determines dose, so a 'safe' concentration can still deliver an unsafe dose to a small child, a heavy drinker, or someone exposed for years. Reading the concentration alone hides who is actually at risk.
Dataset: city drinking-water lead samples (units: parts per billion, ppb).
Measured values: 8, 12, 15, 22, 9 ppb. Average = 13.2 ppb.
Published threshold: EPA lead action level is 15 ppb.
Comparison: The average (13.2) is below 15 ppb, but two individual samples (15 and 22 ppb) meet or exceed the action level, so some homes are over the limit.
Dose estimate: For a 20 kg child drinking 1 liter/day at 22 ppb: 22 micrograms/L times 1 L = 22 micrograms/day, divided by 20 kg = about 1.1 micrograms per kg per day.
Bioaccumulation flag: Flagged. Lead accumulates in bone over time and is eliminated slowly, so repeated daily intake builds up rather than clearing, which raises long-term risk even at concentrations near the threshold.
| Sample | Lead (ppb) | Over 15 ppb action level? |
|---|---|---|
| 1 | 8 | No |
| 2 | 12 | No |
| 3 | 15 | At limit |
| 4 | 22 | Yes |
| 5 | 9 | No |
This model shows the level of evidence and organization needed to complete: Completes the Problem 4 data lab: a dataset analysis comparing measured pollutant concentrations to a published safe threshold, a dose estimate, and a bioaccumulation flag.
- Name the variables and include units.
- Enter observations without changing the raw values.
- Check labels, calculations, and patterns before interpreting the data.
Keep the structure. Replace the question, facts, measurements, and evidence. Then recheck units, vocabulary, and whether the conclusion goes beyond the evidence.
Also due today: Submit your completed data table and written conclusion on Schoology.
- CER:
- Claim, Evidence, Reasoning: make a claim, back it with evidence, explain your reasoning.
- SOP:
- Standard Operating Procedure, the exact steps to follow (especially in a lab).
- Tracker:
- Your PLTW progress log where you record completed evidence.
- myPLTW:
- The PLTW course site where you do the online activities. Find it in Clever with your Microsoft sign-in, right next to Schoology.
Tap the speaker to hear a term. Add two of these to your notebook glossary with a definition and an example in your own words.
Pick just 2 or 3 words from today and make them yours: write what each one means in your own words, name the context clue or evidence that helped, then give one example from what you actually did in Environmental data lab. Try your own words first; the glossary is there if you get stuck. This is voluntary and counts as extra credit, so keep it short.
Saved on this device. Show Mr. Mendoza or add these to your notebook glossary to claim the extra credit.
Classroom documents for this lesson are posted in Schoology. Open Clever, then Schoology, and find each one by the name shown on its card.
Open this when the class reaches this activity and use it to complete the required lesson artifact.
Placement rationale
Matched Environmental exposure and community health by path:Biomedical-Innovations/Problem-4_Environmental-Health/4.1_Environmental-Health; keywords:environmental, water quality. Score 142. Visibility: student-schoology (student-facing resource; link through Schoology rather than local path).
Use this if you were absent, got stuck, or need another pass before you submit the lesson artifact.
Placement rationale
Matched Environmental exposure and community health by path:Biomedical-Innovations/Problem-4_Environmental-Health/4.1_Environmental-Health; keywords:environmental, exposure. Score 138. Visibility: student-schoology (student-facing resource; link through Schoology rather than local path).
Open this when the class reaches this activity and use it to complete the required lesson artifact.
Placement rationale
Matched Environmental exposure and community health by path:Biomedical-Innovations/Problem-4_Environmental-Health/4.1_Environmental-Health; keywords:environmental. Score 134. Visibility: student-schoology (student-facing resource; link through Schoology rather than local path).
Sign in to Clever with your district Microsoft account to open Schoology or myPLTW. Follow today's posted steps. If myPLTW will not open, use the posted alternative and tell Mr. Mendoza. Turn in your completed work through the Schoology assignment.
Practice: try a question, then check your answer▸
Claim ceiling for this check: Today's evidence supports a classroom claim about environmental data lab. It cannot prove causation, diagnose a real patient, or justify action outside this room.
A chemical's measured concentration in a lake is below the safety threshold, yet fish in that lake are unsafe to eat. Give one reason this can happen.
Write an answer and pick a confidence to unlock the key.
Fast retrieval with instant answers, not the commit-then-reveal check above. Try each from memory first: write what you remember about the earlier units, then check yourself here.
Missed class or ready for more?▸
Run this before you touch the bench. It is built from the real lab procedure, so the decisions you make here are the ones you will make with the equipment in your hands. This lesson has more than one, and they cover different skills.
I can name the procedure's purpose and the evidence I will record. I can name today's hazards and the control for each: Never pour iodine waste into the bleach container or any other waste stream. Bleach oxidizes the iodide in Lugol's and drives off iodine vapor, and combining waste streams is how a classroom ends up breathing a gas nobody planned for. My data table is ready before materials are handled.
Finish the checklist before you handle any material.
- • Lugol's iodine stains skin and clothing permanently and irritates the eyes. Goggles, nitrile gloves, and a lab apron go on before the bottle is opened, and the bottle is capped between uses.
- • Iodine is harmful if swallowed. Nothing goes in your mouth, never pipette by mouth, and no food or drink is on the bench today.
- • Iodine on skin: wash with soap and running water for at least 15 minutes. Iodine in an eye: hold the eye open at the eyewash for at least 15 minutes and tell Mr. Mendoza while you are still rinsing.
- • Spill on the bench: keep gloves on, absorb with paper towels working from the outside of the spill inward, put those towels in the chemical waste container, then wipe with water.
- • Never pour iodine waste into the bleach container or any other waste stream. Bleach oxidizes the iodide in Lugol's and drives off iodine vapor, and combining waste streams is how a classroom ends up breathing a gas nobody planned for.
- • All iodine-containing liquid goes into the labeled chemical waste container for disposal per the SDS. Nothing from this lab goes down the sink.
- • Report a chipped or cracked tube before you fill it. Broken glass goes into the labeled broken-glass container, not the regular trash.
- • The starch stock is a laboratory reagent, not food. Do not taste any tube, including the blank.
- • Change the pipette tip at every dilution step. A reused tip carries starch forward and manufactures a false positive at the low end, which is a data problem, not a safety one, but it ruins the run either way.
- • Gloves come off last, then wash your hands with soap and water for 20 seconds before you leave the room.
- 1Before materials are handled, identify the purpose, variables or comparison, controls, measurement units, and stop-work condition.
- 2Write the claim you are testing: below some concentration this test reads negative even though the starch is still in the tube. Predict which tube that will be.
- 3Label eight tubes before anything goes in them: B for the blank, S0 for undiluted stock, S1 through S5 for the dilution series, and U for the coded unknown.
- 4Put 10 mL of distilled water in B, 10 mL of undiluted starch stock in S0, and 9 mL of distilled water in S1 through S5.
- 5Build the 1:10 series. Carry 1 mL of stock into S1 and mix, carry 1 mL of S1 into S2 and mix, and keep going through S5. Change the pipette tip at every single step.
- 6Add two drops of Lugol's iodine to all eight tubes, including B and S0, then start a 60 second timer.
- 7Read every tube against the same white background and record it as positive (blue-black) or negative (the same yellow-brown as the blank).
- 8Name your detection limit, run the coded unknown the same way, and compare your limit to the EPA drinking-water limit you were assigned.
- 9Record each result in the prepared table before interpreting it. Mark missing, repeated, or invalid results truthfully.
- 10Complete the named cleanup and waste route, remove PPE safely, wash hands when required, and confirm the station is ready for the next group.
| Trial or sample ID | Independent condition | Measured result with units | Observation before interpretation | Quality-control note |
|---|---|---|---|---|
Before the procedure, predict the result and cite the rule behind the prediction.
After the procedure, compare the result with the prediction and name one limitation or source of uncertainty.
What today's skills lead to. These are real health-science careers this course builds toward. Tap one to see, on the US Department of Labor's O*NET site, what the job actually involves, what it pays, and how fast it is growing.
Using the posted photographs of a completed dilution series, call every tube positive or negative, state the detection limit with units, and write two sentences on why a negative tube cannot prove a sample is clean. Then find your assigned contaminant in the EPA drinking-water limit table and say whether a test with that detection limit could enforce it.
EPA National Primary Drinking Water RegulationsUse the submission route shown on today's today's page.
Class still runs. Complete the online activity above (it's self-guided). Need the concept taught without a teacher? Use this authoritative explainer:
EPA: Learn About Environmental HealthYou've passed Unit 2, so the optional extra-credit track is open. Complete reserved-unit work from home, including virtual labs, for extra credit. Each item shows its correct submission route.
Open the extra-credit track- CompleteEvery required part of the artifact is present, nothing left blank.
- AccurateThe science and the data are correct and match the evidence.
- Scientific reasoningYou explain your claim with evidence and reasoning (CER), not just an answer.
- Professional communicationClear, organized, labeled, and written the way a clinician or scientist would.
- SubmittedGo to Schoology to turn this in. Submit one PDF. Put your first and last name in the document header. Name the file: FirstName LastName - Assignment Title - YYYY-MM-DD.pdf. If you cannot get in, see Mr. Mendoza. Do not skip the work.
- Error analysis and method · counts doubleName a specific limit of the method and how it moved your result, and compare what you predicted to what happened. "Human error" does not count; say what about the procedure or instrument caused it.
This week
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