Reaction-time lab
Open your materials, follow the steps, then turn in your work.
Measure reaction time under different conditions and record the data.
1. Open your materials
Use the materials named in the first step below. Open lesson resources.
2. Start the work
Set up the ruler-drop or digital reaction-time test and practice once.
Show all 5 required steps
- Set up the ruler-drop or digital reaction-time test and practice once.
- Run baseline trials and record each reaction time in a data table.
- Repeat trials with a distraction condition (such as a second task).
- Average each condition and note which was slower.
- Submit your reaction-time data table with both conditions and averages.
Lost your place? Back after a break? Find your data table. If your baseline trials are recorded (step 2), move to the distraction condition (step 3), then average each condition, note which was slower, and submit the table.
Check your work before submitting
- You can collect reaction-time data with units across conditions.
- You can compute and compare condition averages.
Before lab work: read the safety rules
- Do not test reaction time in conditions that could cause injury (e.g., on a stairway or near equipment).
- The ruler-drop test should be conducted while seated to avoid falls if the subject lunges for the ruler.
- Do not use this lab to make medical claims about cognitive impairment.
3. Turn in your work
DueCheck Schoology- Hand in
- Reaction-time data table with baseline and distraction conditions, all trials with units, condition averages computed, and any outliers flagged with notes.
How to submit and name your file
Submit your completed data table.
In Schoology, open your course and the assignment for this lesson. Attach your file, select Submit, and check that it appears in the submission.
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Check the section number beside Human Anatomy and Physiology in Schoology.
Assignment: Wk9 Data table: Reaction-time lab
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How this lesson connects
Keep using what you learned last class: Many legal medications slow neural signaling, so a driver can be genuinely impaired while breaking no drug law, which is why society has not settled how to assign blame. Today: Reaction time is a single measurable variable that reflects the whole pathway from stimulus to movement, so a consistent multi-trial protocol gives you evidence that adding a distraction lengthens that pathway by a countable amount.
Unit 2 guide: what to keep and use nextOptional: listen or watch a unit review▸
Need help? Warm-up, timing, and directions▸
💡 Big idea: is a single measurable variable that reflects the whole pathway from to movement, so a consistent multi-trial protocol gives you evidence that adding a distraction lengthens that pathway by a countable amount.
- 0-8Setup and one practice trial; establish consistent drop protocol
- 8-20Baseline condition: five trials, record time in ms or cm
- 20-35Distraction condition: five trials with secondary task, record
- 35-50Compute condition averages; flag outliers with notes
- 50-65Peer-check: units present in every row? Averages calculated correctly?
- 65-75Add qualitative observation column: describe how distraction felt
- 75-80Submit
- • Today you measure how fast your nervous system works. is the total time from to motor response.
- • We run two conditions: baseline and distracted. The distraction condition adds cognitive load, so the signal has to compete with other processing.
- • Record every trial with units. Compute the average for each condition. Mark any trial you consider an outlier and say why.
- • Your today feeds directly into Thursday analysis. Clean data now saves time Thursday.
- • Ruler-drop method converts distance (cm) to time (ms) using free-fall kinematics; digital tools measure time directly. Both require consistent protocol for valid comparison.
- • A distraction condition (dual-task) increases because it adds processing load on higher cortical areas, illustrating that conscious processing adds latency beyond the basic arc.
- • Computing a condition average requires recording at least five trials per condition and discarding obvious outliers (fumbled catch, early release).
PLTW connection and today's work
Complete any lab-day check-in or data-entry prompt in Activity 2.1.6 Ready, Set, React! and Activity 2.1.7 Here Comes the Hammer (Lesson 2.1 Getting Nervous) on myPLTW that corresponds to today's reaction-time lab; log it alongside your in-class measurements.
Today's stopping point: Reflex-arc task is done; today the lab task should show complete alongside your data table.
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 2.1.6 Ready, Set, React!
- Activity 2.1.7 Here Comes the Hammer
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.
Many legal medications slow neural signaling, so a driver can be genuinely impaired while breaking no drug law, which is why society has not settled how to assign blame.
is a single measurable variable that reflects the whole pathway from to movement, so a consistent multi-trial protocol gives you evidence that adding a distraction lengthens that pathway by a countable amount.
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: How many milliseconds does adding a distraction actually add to your , and can you measure it precisely enough to prove the difference is real and not just a lucky catch?
What you already know: Many legal medications slow neural signaling, so a driver can be genuinely impaired while breaking no drug law, which is why society has not settled how to assign blame.
New idea: is a single measurable variable that reflects the whole pathway from to movement, so a consistent multi-trial protocol gives you evidence that adding a distraction lengthens that pathway by a countable amount.
Visual or model: F1. F1. A lesson illustration or teaching diagram for Reaction-time lab. Use it with E1-E3; it is a model or context image, not experimental or patient data. What to notice: Trace the labeled structure, movement, or system relationship that connects form to function.
- Observe or measure the relevant feature in reaction-time 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: How many milliseconds does adding a distraction actually add to your , and can you measure it precisely enough to prove the difference is real and not just a lucky catch?
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 fast, automatic response to a that travels through the spinal cord, protecting the body before the brain consciously decides to act.
- • : The short interval between when a appears and when a person responds to it, reflecting how fast the nervous system processes signals.
- • : Any change in the environment, such as light, sound, or temperature, that a living thing can detect and respond to.
- • response: The body's reaction to a detected , carried out by muscles or glands to adjust to a change in the internal or external environment.
- • : A fatty insulating layer wrapped around nerve fibers that speeds up the electrical signals traveling along them.
- • : A , often on the cell surface, that binds a specific signal molecule and triggers a response inside the cell.
- • : The muscle, gland, or other part that carries out the body's response to a signal, acting on the command sent from a control center.
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.
Nervous-system function emerges from specialized structures that receive, integrate, and transmit signals, while observed behavior reflects multiple pathways and sources of variation.
Limit: A diagram, dissection, test, or reaction-time result cannot isolate every neural process or diagnose a neurological condition.
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 collect reaction-time data with units across conditions.
Limit: E3 defines the classroom product or success criterion. It is not independent scientific evidence and cannot justify a clinical or causal claim.
PLTW-HAP-2027-03-17 · Simulated classroom evidence scenario
Your role: anatomy and physiology consultant
Decision: Your team must decide what the evidence from reaction-time lab supports before submitting the labeled and result claim named on today's page.
- • Run at least five trials per condition and compare averages, discarding obvious fumbles before claiming distraction added delay.
- • Take your one best catch as your , since a clean trial shows what your body can really do.
- • Time the same catches with an independent electronic timer, since your classroom method has nothing accurate to check itself against.
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 reaction-time lab. It cannot prove causation, diagnose a real patient, or justify action outside this room.
- • The solution must address the stated need in reaction-time 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 think one trial (or one great catch) is enough to know their .. The trap: It is a trap because a single trial mixes real with noise: a fumbled catch or an early release can swing the number wildly. You need at least five trials per condition and you discard obvious outliers, because only an average across repeated trials reflects your actual pathway speed.
Method: ruler-drop, distance converted to time in milliseconds. Five trials per condition.
Baseline condition (no distraction):
- Trial 1: 210 ms
- Trial 2: 195 ms
- Trial 3: 205 ms
- Trial 4: 380 ms (flagged outlier: fumbled catch, excluded)
- Trial 5: 200 ms
Baseline average (excluding outlier): 202.5 ms
Distraction condition (counting backward aloud):
- Trial 1: 265 ms
- Trial 2: 280 ms
- Trial 3: 255 ms
- Trial 4: 270 ms
- Trial 5: 260 ms
Distraction average: 266 ms
Which was slower: the distraction condition was slower by about 63.5 ms.
| Trial | Baseline (ms) | Distraction (ms) |
|---|---|---|
| 1 | 210 | 265 |
| 2 | 195 | 280 |
| 3 | 205 | 255 |
| 5 | 200 | 260 |
| Average | 202.5 | 266 |
This model shows the level of evidence and organization needed to complete: A reaction-time data table recording multiple trials in a baseline and a distraction condition with units, condition averages computed, and any outliers flagged with a note.
- 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.
- 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 Reaction-time 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.
Hand-picked readings, videos, and interactives for this lesson, all free and from authoritative open organizations (NIH, CDC, OpenStax, Khan Academy, PhET, HHMI, and more).
A fillable, Cornell-style notebook for Unit 2: Research Ready. Type your notes, cues, and summaries right in the PDF, or print it and write by hand. Each lesson page has a cue column, a notes column, and a summary box, plus dated lab-record pages you can turn in.
HBS Unit 2 notebook: Research Ready Fillable PDFCornell notes + lab recordsOpenVetted 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.
Practice: try a question, then check your answer▸
Claim ceiling for this check: Today's evidence supports a classroom claim about reaction-time lab. It cannot prove causation, diagnose a real patient, or justify action outside this room.
Your baseline reaction time averages 220 ms. In the distraction (dual-task) condition your average is 290 ms. Which nervous-system idea explains the 70 ms increase?
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.
I can name the procedure's purpose and the evidence I will record. I can state today's specific hazards and the control for each. If this deck does not name them, I ask Mr. Mendoza before I touch anything. My data table is ready before materials are handled.
Finish the checklist before you handle any material.
- • Do not test reaction time in conditions that could cause injury (e.g., on a stairway or near equipment).
- • The ruler-drop test should be conducted while seated to avoid falls if the subject lunges for the ruler.
- • Do not use this lab to make medical claims about cognitive impairment.
- 1Before materials are handled, identify the purpose, variables or comparison, controls, measurement units, and stop-work condition.
- 2Set up the ruler-drop or digital reaction-time test and practice once.
- 3Run baseline trials and record each reaction time in a data table.
- 4Repeat trials with a distraction condition (such as a second task).
- 5Average each condition and note which was slower.
- 6Submit your reaction-time data table with both conditions and averages.
- 7Record each result in the prepared table before interpreting it. Mark missing, repeated, or invalid results truthfully.
- 8Complete 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 linked simulation or the online ruler-drop method to record reaction-time trials in a baseline and a distraction condition, build a with averages, and submit it.
PhET SimulationsSubmit your completed data table.
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: Neurons and Synapses- 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.
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