Vocabulary Check
What is the group that receives the independent variable?
Experimental Group
in the question, “Does fertilizer affect plant height?” → which is the independent variable?
fertilizer
The group that does not get the independent variable.
Control Group
What kind of graph is best for comparing two sets of data over time?
Double line graph
Why do scientists use large sample sizes in experiments?
To increase accuracy and reliability of results.
The variable that scientists measure
Dependent variable
In the same question, what is the dependent variable?
Plant Height
Why are control variables important?
They ensure only one variable is tested so results are valid.
A student’s data shows that as beaver populations increase, aspen tree numbers decrease. What kind of relationship is this?
A hypothesis is best described as…
A testable prediction based on observations.
Fake medication used in clinical trials
Placebo
Fill in the blanks: “Does ___ affect ___?” → The first blank is the _______ variable.
Independent variable
In a drug trial, one group gets medicine, the other gets a sugar pill. Which group is the control?
The sugar pill group
Why are graphs useful in scientific inquiry?
They show patterns visually and make it easier to draw conclusions.
In clinical trials, why are placebos given to some participants?
To compare real treatment effects vs. psychological/placebo effects.
Variables that must remain the same in an experiment.
Control Variables
A student tests if sunlight affects bean plant growth. Name 2 things they should keep constant.
Amount of water, cup size, type of bean plant... etc
Name two examples of control variables in an experiment testing how temperature affects enzyme activity.
Same enzyme, same test tube size, same pH, same amount of protein, same time.
In the pepsin enzyme experiment, what is the dependent variable?
Amount of protein digested.
A scientist tests a new blood pressure drug. What data should they collect to determine if the drug works?
Patients’ blood pressure before and after treatment.
Methods scientists use to study the natural world
The scientific inquiry
True or False: The dependent variable is the one scientists purposely change.
False
Explain why an experiment testing multiple variables at once is invalid.
Scientists can't tell which variable caused the results
In the photosynthesis experiment, what is the independent variable? (Light distance vs. bubbles released)
Distance from light (light intensity).
What makes a conclusion valid in an experiment?
It is based on evidence, controlled variables, and repeatable results.