Variables and controls
Wed, Apr 7, 2027 · Week 12 · Human Anatomy & Physiology (Human Body Systems)
Today's goal: Define independent, dependent, and controlled variables using teacher notes and the PLTW online task.
This is a model of the work you should turn in today. Use it to check your own: match the structure and the level of detail, do not copy it. Your data and wording should be your own.
Sample experiment: Testing whether a low dose of copper in the water changes how fast C. elegans worms move.
- Independent variable (what I change): the amount of copper added to the water (0, low, medium).
- Dependent variable (what I measure): the worms' movement speed (body bends per minute).
- Controlled variables (held constant): temperature, food amount, age of the worms, dish size, observation time.
Confounding variable example: if the copper dishes were also kept warmer than the control dishes, then temperature would be confounded with copper, and I could not tell whether slower movement came from the copper or the heat.
This model shows the level of evidence and organization needed to complete: A sample experiment with the independent, dependent, and controlled variables correctly identified, plus a written example of a confounding variable.
- Date and label the entry.
- Record the procedure, observation, or design decision clearly.
- End with what the evidence means and the next step.
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 labeled experiment on Schoology.
Turn in: Labeled experiment with variables
Go 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.
Open Schoology PDF upload helpIf you cannot get in, see Mr. Mendoza. Do not skip the work.
Claim ceiling: Today's evidence supports a classroom claim about today's lesson. It cannot prove causation, diagnose a real patient, or justify action outside this room.
One exam-style question that uses exactly what you practiced today. Try it before you reveal the answer, then read why each choice is right or wrong.
Tap an answer to see the full explanation. Nothing is recorded or graded.
It builds this reusable test skill: Identifying independent, dependent, and controlled variables in an experiment.
- Name the concept or data pattern being tested.
- Cross out choices that violate that rule or the evidence.
- Justify the best remaining choice before checking the answer.