Worksheet on identifying independent and dependent variables in various scientific scenarios.
A worksheet titled "Independent and Dependent Variables Scenarios" with eight scenarios involving scientific experiments, each with an image and columns for identifying the independent and dependent variables.
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Step-by-step solution for: Independent and Dependent Variables Scenarios | PDF
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Show Answer Key & Explanations
Step-by-step solution for: Independent and Dependent Variables Scenarios | PDF
Looking at this worksheet, I need to understand what independent and dependent variables are.
The independent variable is what the experimenter changes or controls — it’s the “cause” in the experiment.
The dependent variable is what is measured or observed — it’s the “effect” that might change because of the independent variable.
Let me go through each scenario one by one to check if the answers given are correct.
---
Scenario 1: Cow with growth hormone
- Independent: Growth hormone (correct — this is what’s being changed)
- Dependent: Weight/mass (correct — this is what’s being measured)
✔ Correct
---
Scenario 2: Mosquito repellent on arms
- Independent: Mosquito repellent (correct — one arm gets it, one doesn’t)
- Dependent: Number of mosquito bites (correct — this is what’s counted)
✔ Correct
---
Scenario 3: Grape in tap water vs salt water
- Independent: Salt Water → This is misleading. The real independent variable is the *type of water* (tap vs salt). “Salt Water” alone isn’t accurate — it should be “Type of water” or “Water type”.
- Dependent: Mass → Actually, the scenario says “change in their mass”, so it should be “Change in mass” not just “Mass”.
⚠️ Partially incorrect — needs correction.
---
Scenario 4: Two cars slamming brakes at 60 mph
- Independent: Slam on the brakes → But both cars do the same thing! The scenario doesn’t say they’re different — it says “both cars slam on the brakes”. So there’s no actual independent variable being tested here unless we assume something else (like different car types?), but the scenario doesn’t mention that.
Wait — re-reading: “Two different cars are traveling at 60 mph... both cars slam on the brakes.” It doesn’t say they’re different brands or models — just “different cars”. If they’re truly identical in all ways except maybe brand, then perhaps the independent variable is “Car type” or “Brand of car”? But the answer says “Slam on the brakes” — which is the same for both. That can’t be right.
Actually, looking again — the scenario doesn’t specify any difference between the cars except maybe implied “different cars” meaning different models? But even then, slamming brakes is an action, not a variable being tested.
This seems confused. The independent variable should be what’s different between the two groups — if the cars are different, then “Type of car” might be independent. But the answer says “Slam on the brakes” — which is constant.
Also, dependent variable: “Distance Measurement” — yes, distance to stop is measured.
But independent variable is wrong.
✘ Incorrect
---
Scenario 5: Pillbugs choosing wet vs dry environment
- Independent: Container → No! The container is the same. What’s different is the *environment inside* — wet vs dry. So independent variable should be “Environment type” or “Moisture level”.
- Dependent: Time → Yes, time spent on each side is measured.
⚠️ Independent variable is wrong.
---
Scenario 6: Stapler jamming test
- Independent: 100 Staple → This is the number of staples used — but actually, the independent variable is the *brand of stapler*, since one brand jams 5 times, another 22 times. “100 Staple” is part of the method, not the variable being tested.
- Dependent: Times / Usage → Should be “Number of jams” or “Jam frequency”
⚠️ Both are poorly worded. Independent should be “Stapler brand”, dependent should be “Number of jams”.
---
Scenario 7: Cockroaches exposed to pesticide
- Independent: Pesticide → Yes, exposure to pesticide is what’s being applied.
- Dependent: Percents / Numbers → Should be “Percentage of insects dead” or “Number of dead insects”
⚠️ Dependent variable is vague — should be clearer.
---
Scenario 8: Plants grown with microwaved vs regular water
- Independent: Microwaved Water → Should be “Type of water” (microwaved vs tap)
- Dependent: Height → Correct — height is measured after 2 weeks.
⚠️ Independent variable could be clearer.
---
Now, the instruction says: “Start answering from number 3.”
So I need to correct scenarios 3 through 8.
Let me rewrite them properly:
---
3. One grape is placed in tap water and another grape is placed in salt water. The change in their mass is measured after a day.
→ Independent Variable: Type of water (tap water vs salt water)
→ Dependent Variable: Change in mass
---
4. Two different cars are traveling at 60 mph. At a certain point, both cars slam on the brakes. The distance it takes for each car to stop is then measured.
Assuming “different cars” means different makes/models, then:
→ Independent Variable: Car type (or brand/model)
→ Dependent Variable: Stopping distance
*(Note: If the cars are identical except for some unmentioned factor, the scenario is flawed — but based on context, we assume car type is the variable.)*
---
5. Pillbugs are placed in a container where they have a choice of a wet or a dry environment. Researchers record how much time was spent on each side.
→ Independent Variable: Environment type (wet vs dry)
→ Dependent Variable: Time spent on each side
---
6. A stapler is used to staple 100 papers, it jams 5 times during the trial. A different brand of stapler performs the same test, it jams 22 times.
→ Independent Variable: Brand of stapler
→ Dependent Variable: Number of jams
---
7. Cockroaches are exposed to a pesticide. After 3 hours, 95% of the insects are dead.
→ Independent Variable: Exposure to pesticide (or presence of pesticide)
→ Dependent Variable: Percentage of insects dead
---
8. Two plants are grown using the same light and pots. One plant is given water that has been microwaved and the other plant is given regular tap water. Their height is measured after 2 weeks.
→ Independent Variable: Type of water (microwaved vs tap water)
→ Dependent Variable: Plant height
---
Final Answer:
For scenarios 3–8, corrected independent and dependent variables are:
3. Independent: Type of water; Dependent: Change in mass
4. Independent: Car type; Dependent: Stopping distance
5. Independent: Environment type (wet/dry); Dependent: Time spent on each side
6. Independent: Brand of stapler; Dependent: Number of jams
7. Independent: Exposure to pesticide; Dependent: Percentage of insects dead
8. Independent: Type of water; Dependent: Plant height
The independent variable is what the experimenter changes or controls — it’s the “cause” in the experiment.
The dependent variable is what is measured or observed — it’s the “effect” that might change because of the independent variable.
Let me go through each scenario one by one to check if the answers given are correct.
---
Scenario 1: Cow with growth hormone
- Independent: Growth hormone (correct — this is what’s being changed)
- Dependent: Weight/mass (correct — this is what’s being measured)
✔ Correct
---
Scenario 2: Mosquito repellent on arms
- Independent: Mosquito repellent (correct — one arm gets it, one doesn’t)
- Dependent: Number of mosquito bites (correct — this is what’s counted)
✔ Correct
---
Scenario 3: Grape in tap water vs salt water
- Independent: Salt Water → This is misleading. The real independent variable is the *type of water* (tap vs salt). “Salt Water” alone isn’t accurate — it should be “Type of water” or “Water type”.
- Dependent: Mass → Actually, the scenario says “change in their mass”, so it should be “Change in mass” not just “Mass”.
⚠️ Partially incorrect — needs correction.
---
Scenario 4: Two cars slamming brakes at 60 mph
- Independent: Slam on the brakes → But both cars do the same thing! The scenario doesn’t say they’re different — it says “both cars slam on the brakes”. So there’s no actual independent variable being tested here unless we assume something else (like different car types?), but the scenario doesn’t mention that.
Wait — re-reading: “Two different cars are traveling at 60 mph... both cars slam on the brakes.” It doesn’t say they’re different brands or models — just “different cars”. If they’re truly identical in all ways except maybe brand, then perhaps the independent variable is “Car type” or “Brand of car”? But the answer says “Slam on the brakes” — which is the same for both. That can’t be right.
Actually, looking again — the scenario doesn’t specify any difference between the cars except maybe implied “different cars” meaning different models? But even then, slamming brakes is an action, not a variable being tested.
This seems confused. The independent variable should be what’s different between the two groups — if the cars are different, then “Type of car” might be independent. But the answer says “Slam on the brakes” — which is constant.
Also, dependent variable: “Distance Measurement” — yes, distance to stop is measured.
But independent variable is wrong.
✘ Incorrect
---
Scenario 5: Pillbugs choosing wet vs dry environment
- Independent: Container → No! The container is the same. What’s different is the *environment inside* — wet vs dry. So independent variable should be “Environment type” or “Moisture level”.
- Dependent: Time → Yes, time spent on each side is measured.
⚠️ Independent variable is wrong.
---
Scenario 6: Stapler jamming test
- Independent: 100 Staple → This is the number of staples used — but actually, the independent variable is the *brand of stapler*, since one brand jams 5 times, another 22 times. “100 Staple” is part of the method, not the variable being tested.
- Dependent: Times / Usage → Should be “Number of jams” or “Jam frequency”
⚠️ Both are poorly worded. Independent should be “Stapler brand”, dependent should be “Number of jams”.
---
Scenario 7: Cockroaches exposed to pesticide
- Independent: Pesticide → Yes, exposure to pesticide is what’s being applied.
- Dependent: Percents / Numbers → Should be “Percentage of insects dead” or “Number of dead insects”
⚠️ Dependent variable is vague — should be clearer.
---
Scenario 8: Plants grown with microwaved vs regular water
- Independent: Microwaved Water → Should be “Type of water” (microwaved vs tap)
- Dependent: Height → Correct — height is measured after 2 weeks.
⚠️ Independent variable could be clearer.
---
Now, the instruction says: “Start answering from number 3.”
So I need to correct scenarios 3 through 8.
Let me rewrite them properly:
---
3. One grape is placed in tap water and another grape is placed in salt water. The change in their mass is measured after a day.
→ Independent Variable: Type of water (tap water vs salt water)
→ Dependent Variable: Change in mass
---
4. Two different cars are traveling at 60 mph. At a certain point, both cars slam on the brakes. The distance it takes for each car to stop is then measured.
Assuming “different cars” means different makes/models, then:
→ Independent Variable: Car type (or brand/model)
→ Dependent Variable: Stopping distance
*(Note: If the cars are identical except for some unmentioned factor, the scenario is flawed — but based on context, we assume car type is the variable.)*
---
5. Pillbugs are placed in a container where they have a choice of a wet or a dry environment. Researchers record how much time was spent on each side.
→ Independent Variable: Environment type (wet vs dry)
→ Dependent Variable: Time spent on each side
---
6. A stapler is used to staple 100 papers, it jams 5 times during the trial. A different brand of stapler performs the same test, it jams 22 times.
→ Independent Variable: Brand of stapler
→ Dependent Variable: Number of jams
---
7. Cockroaches are exposed to a pesticide. After 3 hours, 95% of the insects are dead.
→ Independent Variable: Exposure to pesticide (or presence of pesticide)
→ Dependent Variable: Percentage of insects dead
---
8. Two plants are grown using the same light and pots. One plant is given water that has been microwaved and the other plant is given regular tap water. Their height is measured after 2 weeks.
→ Independent Variable: Type of water (microwaved vs tap water)
→ Dependent Variable: Plant height
---
Final Answer:
For scenarios 3–8, corrected independent and dependent variables are:
3. Independent: Type of water; Dependent: Change in mass
4. Independent: Car type; Dependent: Stopping distance
5. Independent: Environment type (wet/dry); Dependent: Time spent on each side
6. Independent: Brand of stapler; Dependent: Number of jams
7. Independent: Exposure to pesticide; Dependent: Percentage of insects dead
8. Independent: Type of water; Dependent: Plant height
Parent Tip: Review the logic above to help your child master the concept of independent and dependent variables worksheet.
