Science Worksheet: Identifying Variables | PDF - Free Printable

Let’s go through each problem one by one. We’re identifying three types of variables in experiments:

- Independent variable: What the scientist changes on purpose.
- Dependent variable: What is measured or observed as a result (what changes because of the independent variable).
- Control variable: What stays the same to make sure the test is fair.

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Problem 1:
> Two groups of sixth graders were tested to compare their speed in solving long division problems. One group had calculators, the other didn’t.

- The thing being changed: whether they use calculators → Independent variable
- What’s being measured: how fast they solve problems → Dependent variable
- What should stay the same: grade level, type of problems, time allowed, etc. → Control variable

✔ So:
- Dependent variable: Speed in solving long division problems
- Independent variable: Use of calculators
- Control variable: Grade level, problem difficulty, time limit, etc.

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Problem 2:
> Students of different grades were given the same jigsaw puzzle to see at what age it was easiest to assemble.

Wait — this says “students of different grades” but then asks “at what age it was easiest”. That’s a bit confusing. Let’s assume they mean students of different ages/grades did the same puzzle.

- What’s being changed: age/grade of student → Independent variable
- What’s being measured: how easy/fast they assemble the puzzle → Dependent variable
- What stays the same: the puzzle itself, instructions, environment → Control variable

✔ So:
- Dependent variable: Ease or time to assemble the puzzle
- Independent variable: Age or grade of student
- Control variable: The puzzle, testing conditions

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Problem 3:
> Sasha watered her plants with cola, lemonade, and just water. After one week, she measured which had grown the most.

- What’s being changed: type of liquid (cola, lemonade, water) → Independent variable
- What’s being measured: plant growth → Dependent variable
- What stays the same: plant type, pot size, sunlight, amount of liquid → Control variable

✔ So:
- Dependent variable: Plant growth
- Independent variable: Type of liquid used
- Control variable: Plant type, pot, sunlight, amount of liquid

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Problem 4:
> Mini put Miracle Grow on first pot, Scotts Fertilizer on second, no fertilizer on third. All are Marigolds.

- What’s being changed: type of fertilizer (or none) → Independent variable
- What’s being measured: plant growth (implied) → Dependent variable
- What stays the same: plant type (Marigolds), pot size, water, sunlight → Control variable

✔ So:
- Dependent variable: Plant growth
- Independent variable: Type of fertilizer (Miracle Grow, Scotts, none)
- Control variable: Plant type, pot, water, sunlight

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Problem 5:
> Lady used eating apples to help her do better on classwork. First day: 0 apples, 1 correct answer. Second day: 1 apple, 2 correct. Third day: 2 apples, 3 correct. She recorded grades each day.

This is a bit messy — it sounds like she’s testing if eating apples improves her classwork performance.

- What’s being changed: number of apples eaten per day → Independent variable
- What’s being measured: number of correct answers (grades) → Dependent variable
- What stays the same: subject, teacher, time of day, etc. → Control variable

✔ So:
- Dependent variable: Number of correct answers (grades)
- Independent variable: Number of apples eaten
- Control variable: Subject, teacher, time of day, etc.

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Final Answer:
1. Dependent: Speed solving problems; Independent: Calculator use; Control: Grade level, problem type
2. Dependent: Puzzle assembly ease/time; Independent: Student age/grade; Control: Puzzle, conditions
3. Dependent: Plant growth; Independent: Liquid type; Control: Plant, pot, light, amount
4. Dependent: Plant growth; Independent: Fertilizer type; Control: Plant, pot, water, light
5. Dependent: Correct answers/grades; Independent: Apples eaten; Control: Subject, teacher, time