Hypothesis and Variables Worksheet One - A classroom activity for students to practice identifying variables and forming hypotheses.

Let’s go step by step to fill out this worksheet.

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Part 1: Definitions

We need to define these terms simply:

- Hypothesis: A guess or prediction about what will happen in an experiment. It’s usually written as “If… then…”
→ *Example: If I water plants more, then they will grow taller.*

- Independent variable: The thing you change on purpose in the experiment.
→ *Example: How much water you give each plant.*

- Dependent variable: The thing you measure — it changes because of the independent variable.
→ *Example: How tall the plants grow.*

- To determine the dependent variable, what question can you ask yourself?
→ Ask: *“What am I measuring?”* or *“What changed because of my test?”*

- To determine the independent variable, what question can you ask yourself?
→ Ask: *“What did I change on purpose?”* or *“What is different between groups?”*

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Part 2: Scenarios

For each scenario, we identify:
- IV = Independent Variable (what’s being tested/changed)
- DV = Dependent Variable (what’s being measured)
- Hypothesis = A smart guess using “If… then…”

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Scenario 1:
> Can ostriches hold their breath longer than people who smoke?

- IV: Type of subject (ostrich vs. smoker) → Actually, better phrasing: Whether the subject is an ostrich or a human smoker.
But since we’re comparing two groups, the IV is “type of creature/person” (ostrich or smoking human).

Wait — actually, let’s think: We are testing if ostriches can hold breath longer than smokers. So we’re changing the type of subject.

Better way:
→ IV: Subject type (ostrich or human smoker)
→ DV: Time holding breath (in seconds or minutes)
→ Hypothesis: If the subject is an ostrich, then it will hold its breath longer than a human who smokes.

*(Note: In real science, we’d control for age, health, etc., but for this level, keep it simple.)*

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Scenario 2:
> What effect does attendance have on students’ grades in science class?

- IV: Attendance (how many days student attends class)
→ Could be measured as number of absences or percent attendance.

- DV: Science grade (like percentage or letter grade)

- Hypothesis: If a student has higher attendance, then their science grade will be higher.

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Scenario 3:
> At what grade level do students grow the quickest?

This one is tricky — it’s asking for comparison across grade levels.

- IV: Grade level (e.g., 6th, 7th, 8th grade)
→ This is what we’re changing/comparing.

- DV: Growth rate (how many inches/cm grown in a year)
→ Or total growth over a set time.

- Hypothesis: If a student is in 7th grade, then they will grow faster than students in 6th or 8th grade.
*(You could pick any grade — just make a reasonable guess. Many kids grow fastest around puberty, which often hits in 7th grade.)*

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Scenario 4:
> Is riding the bus or riding in a quicker way to get to school?

Typo? Probably meant: “Is riding the bus or riding in a car a quicker way to get to school?”

Assuming that’s the case:

- IV: Mode of transportation (bus vs. car)
→ What we’re changing/testing.

- DV: Time it takes to get to school (minutes)

- Hypothesis: If I ride in a car, then I will get to school faster than if I ride the bus.

*(Again, depends on traffic, distance, etc., but for hypothesis, just make a logical guess.)*

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Now, let’s write everything neatly for the final answer.

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Final Answer:

Definitions:

- Hypothesis: A prediction about what will happen in an experiment, often written as “If… then…”
- Independent variable: The thing you change on purpose in the experiment.
- Dependent variable: The thing you measure — it changes because of the independent variable.
- To determine the dependent variable, ask: *“What am I measuring?”*
- To determine the independent variable, ask: *“What did I change on purpose?”*

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Scenarios:

1. Ostriches vs. Smokers – Breath Holding

- IV: Type of subject (ostrich or human smoker)
- DV: Time holding breath (seconds/minutes)
- Hypothesis: If the subject is an ostrich, then it will hold its breath longer than a human who smokes.

2. Attendance and Science Grades

- IV: Student attendance (number of days present)
- DV: Science grade (percentage or letter grade)
- Hypothesis: If a student has higher attendance, then their science grade will be higher.

3. Fastest Growth by Grade Level

- IV: Grade level (6th, 7th, 8th, etc.)
- DV: Amount of growth in one year (inches or cm)
- Hypothesis: If a student is in 7th grade, then they will grow faster than students in other grades.

4. Bus vs. Car – Getting to School

- IV: Mode of transportation (bus or car)
- DV: Time taken to get to school (minutes)
- Hypothesis: If I ride in a car, then I will get to school faster than if I ride the bus.

*(Note: For #4, assuming “riding in a [car]” was intended. If not, adjust accordingly — but based on context, car makes sense.)*