Bart Simpson Controls And Variables With Answers | PDF - Free Printable

It looks like you've uploaded a document titled "Identify the Controls and Variables" that contains several science experiment scenarios, each with questions about identifying the control group, independent variable, dependent variable, and other experimental components.

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🔬 Scenario 1: Snail Population Experiment

> *Students divide their special plant soil into 4 groups of 10 snails each. Group A is given no water. Group B is given 1 mL of water daily. Group C is given 2 mL daily. Group D is given 3 mL daily.*

#### Questions:

1. Control Group?
✔ Group A – This group receives no water, so it serves as the baseline for comparison.

2. Independent Variable?
✔ Amount of water given daily (0 mL, 1 mL, 2 mL, 3 mL) – This is what the students are changing.

3. Dependent Variable?
✔ Population of snails – This is what they are measuring (how many snails survive or grow).

4. What should students conclude from the data?
✔ The conclusion depends on the results, but generally:
> "The amount of water affects snail population growth. More water likely leads to higher survival or reproduction, up to a point."

5. How could this experiment be improved?
✔ Use more than one trial per group to reduce chance variation.
✔ Keep all other conditions the same (light, temperature, food).
✔ Use larger sample sizes (more snails per group).
✔ Include a control with natural moisture levels.

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🧪 Scenario 2: Plant Growth with Water Amounts

> *Hanna notices her houseplant is wilting. She waters it every day. Then she tries watering it once a week. After 2 weeks, the plant is healthier.*

#### Questions:

6. What is the initial observation?
✔ The plant was wilting.

7. Identify the:
- Control Group: The plant before any change (or the original condition).
- Independent Variable: Frequency of watering (daily vs. weekly).
- Dependent Variable: Health of the plant (wilting vs. healthy).

8. Hypothesis:
✔ "If I water the plant less frequently (once a week), then it will become healthier because overwatering may harm it."

9. Dependent Variable’s expectation:
✔ If the hypothesis is correct, the plant should become healthier when watered weekly.

10. What should Hanna's conclusion be?
✔ "Reducing watering frequency improved the plant's health, suggesting overwatering may have been causing the wilting."

11. Could this experiment be improved?
✔ Yes. Use multiple plants, keep light and soil consistent, measure exact health metrics (leaf count, color, size), and run over a longer period.

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🌱 Scenario 3: Plant Growth with Light Duration

> *Harri believes that more exposure to sunlight increases plant growth. He places two identical plants under different lighting conditions: one gets 6 hours of light/day, the other gets 12 hours. After 2 weeks, the 12-hour plant is taller.*

#### Questions:

12. Control Group:
✔ The plant receiving 6 hours of light (baseline condition).

13. Independent Variable:
✔ Duration of light exposure (6 vs. 12 hours)

14. Dependent Variable:
✔ Height of the plant (measured in cm)

15. Conclusion:
✔ "Increasing light exposure from 6 to 12 hours per day increases plant growth."

16. Improvement suggestion:
✔ Use more plants per group, control for temperature, humidity, soil type, and use a ruler to measure height accurately.

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🔬 Scenario 4: Plant Growth with Fertilizer

> *Kenny wants to test if fertilizer helps plant growth. He uses two pots with identical soil and seeds. One gets fertilizer; the other doesn’t. After 2 weeks, the fertilized plant is taller.*

#### Questions:

17. Control Group:
✔ The plant without fertilizer (Group B).

18. Independent Variable:
✔ Presence or absence of fertilizer

19. Dependent Variable:
✔ Plant height (or growth rate)

20. Conclusion:
✔ "Fertilizer promotes plant growth, as the plant receiving it grew taller than the one without."

21. Improvement suggestion:
✔ Use multiple plants per group, ensure same watering and light, measure over time, and use a standardized method for measuring height.

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✔ Summary Table

| Scenario | Control Group | Independent Variable | Dependent Variable |
|--------|----------------|-----------------------|---------------------|
| 1 | Group A (no water) | Amount of water | Snail population |
| 2 | Original plant state / daily watering | Watering frequency | Plant health |
| 3 | 6-hour light plant | Light duration | Plant height |
| 4 | No fertilizer plant | Fertilizer presence | Plant height |

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🎯 Key Concepts Recap:

- Control Group: The group that does not receive the experimental treatment.
- Independent Variable: What you change (the cause).
- Dependent Variable: What you measure (the effect).
- Hypothesis: An educated guess: *"If [IV], then [DV] because..."*
- Improvements: Replication, controlled variables, accurate measurement.

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