The big idea01.01 is the scientific method lesson. The module exam will mix this with 01.02 (shapes/enzymes) and 01.03 (origin of life). The traps: science vs opinion, independent vs dependent, and theory explains / law describes — a theory never becomes a law.
Ideas this lesson assumes
A lot of middle-school science treats “the scientific method” as a poster of five boxes. This lesson is pickier than that, and the exam uses the picky version.
Not sure about the basics underneath this lesson?
You need six labels cold. The rest is matching them to a story.
1
Independent vs dependent
Independent = you change it (fertilizer type, time of day). Dependent = you measure it (height, pH, time). A trick: the dependent “depends” on what you did.
2
Control group vs controlled variables
Control group is a set of plants (or whatever) that gets no treatment. Controlled variables are the knobs you do not turn: same water, same light, same pot size.
3
Theory vs law vs hypothesis
Hypothesis = one testable prediction for this experiment. Theory = big explanation built from many tests. Law = description of what happens. They are three different jobs.
4
Not everything is science
If you cannot observe it or run a fair test, science steps aside. That includes “which ice cream is best” and “is the risk worth it.”
Got it now? Scroll back up and re-read the section — it should land differently.
Words that show up as whole questions
If a stem uses one of these words, pick the matching row.
Idea
What it means
Not the same as
Exam costume
Independent variable
The one factor the scientist changes on purpose.
Not the thing you measure.
“Places the plants are grown” / “which liquid” / “time of day watered.”
Dependent variable
What you measure — it changes in response.
Not the treatment.
Plant height, pH, how fast something grows, time for a reaction.
Controlled variables
Everything you keep the same.
Not the control group.
Same water amount, same plant type, same number of plants per group.
Control group
Same setup, no treatment — the “plain” pot.
Not “controlled variables.”
The pot with no fertilizer so you can see if fertilizer actually did anything.
Scientific theory
A broad explanation of how/why, with lots of evidence.
Not a guess. Never turns into a law.
“Which attempts to explain the natural world?” → theory.
Scientific law
A description of what happens (often a relationship), not why.
Not an explanation.
Gravity, conservation of mass. Describes; does not explain.
Shortcuts that give away the answer
Opinion, morals, “best flavor” → not science.
You change it → independent. You measure it → dependent.
Theory = explains. Law = describes. Theories do not become laws.
What counts as science
Pages 2–3
Science is knowledge of the natural world plus the process of building it: observation, tests, empirical evidence. It has to be observable, testable, replicable, reliable, and flexible (new evidence can change it). Art, philosophy, and religion are valuable — they just are not science, because beliefs and opinions cannot be tested that way. Pseudoscience claims to be science but skips the method or cannot be shown reliable.
Likely on the quizLive-style: “Which question can science answer?” Why is the sky blue — yes. Best ice cream flavor — no. “Is it worth the risk…” is a value question, not a measurement.
Reliable sources, not a commercial
Page 4
Peer review means other scientists check the work before it is published. Reliable: tested more than once, by more than one group, fully documented, facts not mixed with sales pitch, not paid for by someone selling the product, published in a scientific journal.
Likely on the quizA diet-pill ad with a company doctor and “results not typical” is not reliable.
Variables — change one thing
Page 5
A hypothesis predicts how changing the independent variable will affect the dependent variable. Keep everything else constant (controlled variables). The experimental group gets the change; the control group does not. If two things differ at once (paper airplanes that change both wing length and body shape), you cannot tell which difference caused the result — not a valid test.
Likely on the quiz01.04 review: Rose compared red vs blue dye with no control. Missing piece = control.
Not sure about this bit?
If two knobs move, you learned nothing.
1
One change
The farmer changes nutrients only. Water, light, and temperature stay put. Then if the plants grow, you can blame nutrients.
2
The plain pot
That is the control group. Without it you cannot tell “fertilizer helped” from “plants just grow.”
3
The airplane trap
Long wings AND a different body shape. Either one could be why it flew farther. The lesson wants you to say the test is not valid.
Got it now? Scroll back up and re-read the section — it should land differently.
Graphs and conclusions
Page 6
Independent variable on the x-axis, dependent on the y-axis. Line graphs for change over time; bar graphs to compare groups. A conclusion names the finding, summarizes the data, says whether the hypothesis held, and notes limits (John only tested three pots).
Likely on the quizSalt-on-ice data table: more salt → water stays liquid longer → salt lowers the freezing point.
Theory vs law — they stay different
Page 7
A law describes what we expect to happen (gravity, conservation of mass) and does not explain why. A theory is a broad, well-tested explanation (cell theory, plate tectonics). Both are based on lots of evidence. Everyday “in theory” means a guess. In science it does not. Theories never become laws.
Likely on the quiz01.04: “How are laws and theories different?” Correct: a theory is an explanation of a natural phenomenon. Wrong: “theories turn into laws.”
Not sure about this bit?
Everyday English lies to you here.
1
Law
What happens. Drop a rock, it falls. Conservation of mass. No “why” required.
2
Theory
Why/how, with a pile of evidence. Cell theory, plate tectonics. Not a hunch.
3
The wrong movie
People say hypotheses become theories become laws. This course says no. A theory never becomes a law.
Got it now? Scroll back up and re-read the section — it should land differently.