Sense & Science (Observations vs. Inferences)
An observation
What type of data involves numbers, amounts, counts, or measurements?
Quantitative Data.
What do we call the ONE factor that a scientist deliberately changes on purpose in an experiment (the cause)?
Independent Variable (IV)
What is an experimental design called where you change only ONE variable at a time?
A Fair Test
Why is "Which flavor of ice cream tastes the absolute best?" NOT a testable question?
It asks for a personal opinion/preference, which cannot be measured scientifically
An inference
What type of data uses descriptive words to describe qualities like color, shape, or texture?
Qualitative Data
What do we call the factor that is measured to collect data in an experiment (the effect)?
Dependent Variable (DV)
What do we call the "normal" setup in an experiment that receives no special treatment and acts as a baseline comparison?
The Control Group
State the official science formula for writing a testable question.
"How does [Independent Variable] affect [Dependent Variable]?"
Is this an Observation or an Inference? "The sidewalk is wet, so it must have rained last night."
An Inference (you see the wet sidewalk, but infer the rain).
Qualitative or Quantitative? "The runner finished the 100-meter dash in 12.4 seconds."
Quantitative Data (uses a number/measurement)
What is a factor in an experiment that must be kept strictly identical across all trial runs?
A Constant (or Controlled Variable).
What do we call the group in an experiment that receives the special change or treatment (the IV)?
The Experimental Group
Is this question Testable or Non-Testable? "How does the amount of water a plant receives affect its growth in centimeters?"
Testable (has a clear IV and measurable DV)
DAILY DOUBLE: Name the observation AND the inference in this sentence: "The dog is barking because he sees a squirrel in the yard."
Observation: The dog is barking.
Inference: He sees a squirrel.
Qualitative or Quantitative? "The chemical solution has a strong, sweet lemon smell."
Qualitative Data (describes a smell quality)
Marcus tests how ramp height affects toy car distance. What is the Independent Variable and what is the Dependent Variable?
IV: Ramp height. DV: Distance the car travels
(DAILY DOUBLE): David tests if brand-name batteries last longer than store-brand. He puts a brand-name battery in a flashlight in a hot garage, and a store-brand battery in a toy car in a cold house. Name TWO flaws in his setup.
Flaw 1: Device type (flashlight vs. toy car).
Flaw 2: Temperature (hot garage vs. cold house)
Turn this opinion into a testable question using our formula: "Gatorade makes athletes run faster than water."
"How does the type of drink (Gatorade vs. water) affect an athlete's running time/speed?"
Is this an Observation or an Inference? "The liquid in the beaker turned bright green and began to bubble."
An Observation (directly seen/observed)
Give ONE example of qualitative data about your science classroom AND ONE example of quantitative data.
Answers will vary. (e.g., Qualitative: "The desks are black." / Quantitative: "There are 28 chairs.")
How many Independent Variables can you change at one time in a valid experiment, and why?
Exactly ONE. Changing more than one invalidates the test because you won't know which variable caused the results.
A scientist tests a new super-fertilizer on Plant A and gives plain water to Plant B. Identify which plant is the Control Group and which is the Experimental Group.
Plant B (plain water): Control Group.
Plant A (super-fertilizer): Experimental Group
What is a single run or repeat of an experimental test called?
A Trial