Variables and controls
Students will define independent, dependent, and controlled variables using teacher notes and the PLTW online task.
Labeled sample experiment with independent, dependent, and controlled variables identified, plus a written confounding-variable example.
- 1Do thisStudents will define independent, dependent, and controlled variables using teacher notes and the PLTW online task.
- 2Use this resource
- 3Submit thisNotebook check: Labeled sample experiment with independent, dependent, and controlled variables identified, plus a written confounding-variable example.
- 4Submit it here
- 1CMSD website. Go to clevelandmetroschools.org and click the Clever button.
- 2Clever. Clever opens. Sign in if it asks.
- 3Microsoft (district) login. Use your district Microsoft account (the one for school).
- 4Schoology. Open Schoology, then your class, then Assignments, and find the file named below.
The file to submit is named: Human Anatomy & Physiology (Human Body Systems) › Unit 2.2 Research Model: Model organisms, C. elegans, neurotransmitters/hormones, scientific literature, research poster. › Notebook checkOpen 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 — you open it through Schoology.
Minute-by-minute · 80-minute block
💡 Big idea: Controlled experiments isolate one variable at a time so that results can be attributed to a single cause.
- 0-10Warm-up: identify what is wrong with a poorly designed experiment (projected example)
- 10-28Guided notes: independent, dependent, controlled variables, sample size, confounding variables
- 28-45PLTW online variables-identification activity
- 45-60Label variables in a provided sample experiment description
- 60-72Write one confounding variable scenario and share with a partner
- 72-80Submit labeled experiment and PLTW activity confirmation
- • Every valid scientific experiment is built on the same logical structure: change one thing, measure one thing, control everything else.
- • Today you will master that structure using real and sample experiment descriptions.
- • Understanding variables is foundational for designing your own C. elegans investigation later this week.
- • The PLTW online activity will let you practice identifying variables in multiple scenarios.
- 1Take notes on variable types and experimental controls.
- 2Define sample size and explain why it matters.
- 3Complete the PLTW online variables-identification activity.
- 4Label variables in a sample experiment description.
- 5Write one example of a confounding variable.
- • All three variable types are correctly identified in the sample.
- • PLTW online task is submitted complete.
- • The independent variable is deliberately changed; the dependent variable is measured; controlled variables are held constant.
- • Sample size affects the reliability and generalizability of experimental results.
- • Confounding variables introduce alternative explanations and weaken causal conclusions.
Your PLTW work today
Unit 2.2 Research Model: Model organisms, C. elegans, neurotransmitters/hormones, scientific literature, research poster. · Variables and controls
Day 2 of this lesson. Open this exact section in myPLTW (reached through Schoology), then do the work below.
Do this: Complete the variables-identification online activity in myPLTW; work through all independent, dependent, and controlled variable scenarios during the 28-45 minute window.
Mark the variables activity complete in myPLTW after submitting your labeled sample experiment.
Monday's task is done; today the variables task should show complete in your progress bar.
Screenshot or note of completion status for your tracker.
All PLTW activities are completed inside the PLTW course environment — this page only gives direction. Submit producibles on Schoology.
Today's PLTW tracker
Check things off as you work, then submit. This tells Mr. Mendoza how you're doing so he can help the class. It does not replace turning in your producible on Schoology.
Use the code Mr. Mendoza gave you, not your name. Saved on this device.
Unit 2.2 Research Model: Model organisms, C. elegans, neurotransmitters/hormones, scientific literature, research poster. · Variables and controls
Complete the variables-identification online activity in myPLTW; work through all independent, dependent, and controlled variable scenarios during the 28-45 minute window.
Monday's task is done; today the variables task should show complete in your progress bar.
This is how Mr. Mendoza sees the class keeping pace with PLTW. Be honest, it only helps if it is accurate.
🎯 Students will define independent, dependent, and controlled variables using teacher notes and the PLTW online task.
- Take notes on variable types and experimental controls.
- Define sample size and explain why it matters.
- Complete the PLTW online variables-identification activity.
- Label variables in a sample experiment description.
- Write one example of a confounding variable.
Notebook check: Labeled sample experiment with independent, dependent, and controlled variables identified, plus a written confounding-variable example.
Submit on SchoologyUpload by 11:29 PM for full credit.
| Task | Who |
|---|---|
| Take notes on variable types and experimental controls. | _______ |
| Define sample size and explain why it matters. | _______ |
| Complete the PLTW online variables-identification activity. | _______ |
| Label variables in a sample experiment description. | _______ |
| Write one example of a confounding variable. | _______ |
Working solo? Put your own name in "Who" for every row.
- All three variable types are correctly identified in the sample.
- PLTW online task is submitted complete.
Resources & readings
Vetted readings and references for this unit. Use them to prepare, to catch up if you were absent, or to go deeper on today's target.
WebXam practice
Cumulative WebXam review
A quick mixed-review pulling questions from earlier units plus today, so the WebXam material stays fresh.
Where this leads — careers
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.
What to do if you were absent
Today is individual PLTW work, so do exactly what we did in class, from home: complete the same PLTW target above, then submit your Notebook check.
Open Schoology (CMSD) and keep goingHow to get there: open the CMSD website, click Clever, sign in with your Microsoft (district) account, then open Schoology from Clever.
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: The science of biology (experimental design)Optional extra credit (async)
You've passed Unit 2, so the optional extra-credit track is open. Complete reserved-unit work from home (virtual labs included) for extra credit, all submitted on Schoology.
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.
- SubmittedTurned in the right way (Schoology for routine work) and confirmed.
Drop your Thu, Oct 29, 2026 · Variables and controls here. Use a clear file name (your initials + project). Routine work still goes to Schoology (via the CMSD portal).
Upload a project