Graph draft
Open your materials, follow the steps, then turn in your work.
Run a two-fold dilution series to its endpoint, then draft the calibration line that turns an endpoint into a concentration.
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: doubling the starting concentration should push the endpoint exactly one well further down the row. Predict where your endpoint will land.
Show all 6 required steps
- Write the claim you are testing: doubling the starting concentration should push the endpoint exactly one well further down the row. Predict where your endpoint will land.
- Label a row of six wells K1 through K6 for your assigned known concentration, a second row U1 through U6 for the coded unknown, and one more well BL for the blank.
- Put 100 uL of distilled water in wells 2 through 6 of both rows and in BL. Leave K1 and U1 empty for now.
- Put 200 uL of your assigned known sample in K1 and 200 uL of the coded unknown in U1. In each row, move 100 uL from well 1 into well 2 and mix, carry 100 uL along the row through well 6, then discard the last 100 uL. Change the tip at every transfer.
- Add one drop of Lugol's iodine to all thirteen wells, start a 60 second timer, then find the endpoint in each row: the last well still darker than BL.
- Post your known concentration and its endpoint to the class chart, plot the class points, draw the line, and read the unknown off it.
Lost your place? Lost your place? Find your data table (step 1). If your columns are labeled with units, jump to step 2 and pick your graph type. If not, fix the table first, then keep going.
Check your work before submitting
- You can name your endpoint well and say what makes it the endpoint rather than the well beside it.
- You can name your independent variable, your dependent variable, and what the blank rules out.
- You can read a concentration off the class line and state how wide the estimate is and why it cannot be narrower.
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.
- Eject tips straight down into the waste container. Ejecting across the bench flicks droplets of iodine and sample onto neighbors and onto other wells.
- Spill on the bench or in the plate: keep gloves on, absorb with paper towels working from the outside 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.
- The whole plate goes into the labeled chemical waste container at the end, liquid and all. Nothing from this lab goes down the sink.
- The starch stock is a laboratory reagent, not food. Do not taste any well, including the blank.
- Change the tip at every transfer. A reused tip carries the stronger well forward and pushes your endpoint one well too far, which quietly moves the whole class line.
- 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
- Endpoint table with the claim you predicted, your assigned known concentration, your endpoint well number, the blank result, and the pooled class results; a drafted calibration graph with titled and scaled axes; the coded unknown marked on the line with its estimated concentration; and one sentence stating how wide the estimate is and one named limitation of pooling data across teams that pipetted differently.
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: Evidence can only drive a decision when it is integrated, cited, and readable by the people at risk, so a complete exposure map joins pathway, dose, and mitigation into one document a non-scientist can act on and confirms it in the tracker to close the Problem 4 loop. Today: The axis, unit, and outlier decisions you bake into a graph control what a reader concludes, so a rushed graph can broadcast a claim your data never actually supported.
Optional: listen or watch a unit review▸
Need help? Warm-up, timing, and directions▸
💡 Big idea: The axis, unit, and outlier decisions you bake into a graph control what a reader concludes, so a rushed graph can broadcast a claim your data never actually supported.
- 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 both rows and BL, load 100 uL of distilled water into wells 2 through 6 and BL, and record your assigned known concentration
- 25-45 minRun the two-fold series down both rows, changing the tip at every transfer, and discard the last 100 uL
- 45-55 minAdd one drop of Lugol's iodine to all thirteen wells, run the 60 second timer, and call the endpoint in each row
- 55-70 minPost your concentration and endpoint to the class chart, plot the class points, and draw the line with titled, scaled axes
- 70-80 minRead the unknown off the line, note your uncertainty, route iodine waste to the chemical waste container, wipe the bench, wash hands, and submit
- • Welcome back. Today the graph you draw comes from numbers your own hands make in the first half of class.
- • You halve your sample six times and find the last well that still shows color. That well number is your data point.
- • Every team runs a different known concentration, so together the class builds a line no single team could.
- • Then you put the unknown on that line and say how sure you are, which is the harder half.
- • In a two-fold series each well holds half the concentration of the well before it, so the well number counts doublings and is not a linear scale.
- • The endpoint is the last well still darker than the blank, which means every endpoint call depends on the blank being right.
- • A calibration line built from known samples converts a measurement into a concentration, but only inside the range those known samples covered.
- • The is the known starting concentration and the is the endpoint well number; the blank of distilled water plus iodine is the control that defines what negative looks like.
- • A two-fold series can only place an unknown inside a factor-of-two window, so the estimate carries at least one dilution step of uncertainty no matter how carefully you pipette.
PLTW connection and today's work
Open Problem 4 Investigating Environmental Health in your myPLTW course shell and navigate to the current graphing activity, then run your dilution endpoint and draft the calibration graph from the pooled class data.
Today's stopping point: The two no-school days are behind you; graph drafts are a mid-unit milestone, so confirm you are on pace and submit by end of today.
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 4.1.3 Testing the Waters
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.
Evidence can only drive a decision when it is integrated, cited, and readable by the people at risk, so a complete exposure map joins pathway, dose, and mitigation into one document a non-scientist can act on and confirms it in the tracker to close the Problem 4 loop.
The axis, unit, and outlier decisions you bake into a graph control what a reader concludes, so a rushed graph can broadcast a claim your data never actually supported.
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: You have a column of numbers from your environmental data set. Which graph, which axes, and which outlier calls make those numbers say something true instead of something misleading?
What you already know: Evidence can only drive a decision when it is integrated, cited, and readable by the people at risk, so a complete exposure map joins pathway, dose, and mitigation into one document a non-scientist can act on and confirms it in the tracker to close the Problem 4 loop.
New idea: The axis, unit, and outlier decisions you bake into a graph control what a reader concludes, so a rushed graph can broadcast a claim your data never actually supported.
Visual or model: F1. F1. A lesson illustration or teaching diagram for Graph draft. 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 graph draft.
- 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: You have a column of numbers from your environmental data set. Which graph, which axes, and which outlier calls make those numbers say something true instead of something misleading?
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.
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.
A planned study connects its question to defined variables, controls, sampling, measurement, and analysis so the resulting data can support a bounded and reproducible conclusion.
Limit: A statistical difference or trend does not automatically establish practical importance, causation, generalizability, or freedom from bias.
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 name your endpoint well and say what makes it the endpoint rather than the well beside 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-2027-04-13 · Simulated classroom evidence scenario
Your role: biomedical design team member
Decision: Your team must decide what the evidence from graph draft supports before submitting the labeled and result claim named on today's page.
- • Choose whichever graph looks best with your numbers, because bar or line is a style call that leaves data unchanged.
- • Hold the outlier call until a repeat sample shows whether that high value is a real reading or an instrument slip.
- • Match the graph to your variables, using bars for separate categories and a line only for change across time.
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 graph draft. 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 graph draft.
- • 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 Any data can go on any graph, and a bar chart versus a line graph is just a style choice you make to look nice.. The trap: Graph type is a claim about your variables, not a style pick. Bar charts compare separate categories; line graphs show change across a continuous or time axis. Using the wrong one tells the reader a relationship exists (or does not) that your data never showed.
Data: monthly average air particulate (PM2.5) near a roadway, units micrograms per cubic meter.
Clean table columns: Month, PM2.5 (micrograms/m3).
Values: Jan 14, Feb 13, Mar 12, Apr 11, May 9, Jun 35.
Graph choice: line graph, because the variable (month) is time-ordered and I want to show change over time.
Axes: x-axis = Month; y-axis = PM2.5 (micrograms/m3), scaled 0 to 40. Title: 'Monthly Roadway PM2.5'.
Outlier: June (35) is far above the others. I flagged it rather than deleting it, and noted a possible cause (a nearby wildfire smoke event), so the reader can decide how to treat it.
Trend sentence: Particulate levels declined from January through May, then spiked sharply in June.
| Month | PM2.5 (ug/m3) |
|---|---|
| Jan | 14 |
| Feb | 13 |
| Mar | 12 |
| Apr | 11 |
| May | 9 |
| Jun | 35 (outlier, flagged) |
This model shows the level of evidence and organization needed to complete: Completes the Problem 4 graph-draft step: an organized data table plus a drafted graph with titled, scaled axes, an outlier decision, and a one-sentence trend statement.
- 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 data table and graph draft on Schoology today.
- 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.
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 data graphing and analysis 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).
Use this if you were absent, got stuck, or need another pass before you submit the lesson artifact.
Placement rationale
Matched Environmental data graphing and analysis by path:Biomedical-Innovations/Problem-4_Environmental-Health/4.1_Environmental-Health; keywords:environmental. Score 130. 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 data graphing and analysis by path:Biomedical-Innovations/Problem-4_Environmental-Health/4.1_Environmental-Health; keywords:environmental. Score 130. 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 graph draft. It cannot prove causation, diagnose a real patient, or justify action outside this room.
Your data is monthly air-quality readings for one year. A classmate plots them as a bar chart with the y-axis starting at 40. Name the two problems and fix them.
Write an answer and pick a confidence to unlock the key.
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.
- • Eject tips straight down into the waste container. Ejecting across the bench flicks droplets of iodine and sample onto neighbors and onto other wells.
- • Spill on the bench or in the plate: keep gloves on, absorb with paper towels working from the outside 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.
- • The whole plate goes into the labeled chemical waste container at the end, liquid and all. Nothing from this lab goes down the sink.
- • The starch stock is a laboratory reagent, not food. Do not taste any well, including the blank.
- • Change the tip at every transfer. A reused tip carries the stronger well forward and pushes your endpoint one well too far, which quietly moves the whole class line.
- • 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: doubling the starting concentration should push the endpoint exactly one well further down the row. Predict where your endpoint will land.
- 3Label a row of six wells K1 through K6 for your assigned known concentration, a second row U1 through U6 for the coded unknown, and one more well BL for the blank.
- 4Put 100 uL of distilled water in wells 2 through 6 of both rows and in BL. Leave K1 and U1 empty for now.
- 5Put 200 uL of your assigned known sample in K1 and 200 uL of the coded unknown in U1. In each row, move 100 uL from well 1 into well 2 and mix, carry 100 uL along the row through well 6, then discard the last 100 uL. Change the tip at every transfer.
- 6Add one drop of Lugol's iodine to all thirteen wells, start a 60 second timer, then find the endpoint in each row: the last well still darker than BL.
- 7Post your known concentration and its endpoint to the class chart, plot the class points, draw the line, and read the unknown off it.
- 8Record each result in the prepared table before interpreting it. Mark missing, repeated, or invalid results truthfully.
- 9Complete 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.
Use the posted class endpoint chart to plot known concentration against endpoint well number, draw the line, place the coded unknown on it, and write one sentence on how wide the estimate is and why a two-fold series cannot do better.
Khan Academy: reading and making graphsUse 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:
Khan Academy StatisticsYou'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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