Science worksheet designed to help students practice identifying independent, dependent, and constant variables through real-world scenarios.

It looks like you've uploaded an image of a worksheet titled "Identifying Variables" that contains five scenarios. Each scenario describes an experiment, and the task is to identify the independent variable, dependent variable, and control in each case.

Since I can't view images directly, I’ll help you solve this based on the text you provided (assuming it's clear enough). Let me walk through each scenario step by step and explain how to identify the variables.

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Scenario 1:

> Lena wants to see if the size of the plant affects how fast the plant grows. She plants seeds in three pots. One pot has a small seed, one has a medium seed, and one has a large seed. After 2 weeks she observes which size of seed grows fastest.

- Independent Variable: The size of the seed (small, medium, large) — this is what Lena is changing.
- Dependent Variable: How fast the plant grows (growth rate) — this is what is being measured.
- Control: The conditions that remain constant — such as amount of water, sunlight, soil type, temperature, etc. These are not mentioned explicitly but assumed to be kept the same.

✔ Answer:
- Independent Variable: Size of the seed
- Dependent Variable: Growth rate of the plant
- Control: Amount of water, sunlight, soil, temperature, etc.

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Scenario 2:

> Brock is studying whether the hour of the day will make his teeth whiter. He uses a new brand of toothpaste called "Sparkle Clean". Brock waits 20 days then with Sparkle Clean and 20 days with the original toothpaste. After he sees the results, he concludes that the toothpaste makes his teeth whiter.

Wait — this scenario seems to have a flaw. Brock is testing two different toothpastes, but the question says he’s testing the “hour of the day.” That doesn’t match the action described.

Let’s re-read:
> “Brock is studying whether the hour of the day will make his teeth whiter.”

But then he uses two different toothpastes for 20 days each. So the actual variable being tested appears to be toothpaste brand, not time of day.

This suggests a mismatch. But assuming the intended variable is type of toothpaste, here’s the correct analysis:

- Independent Variable: Type of toothpaste (Sparkle Clean vs. original)
- Dependent Variable: Whiteness of teeth
- Control: Brushing time, frequency, diet, water intake, brushing technique, etc.

⚠️ However, if the hour of the day was meant to be the independent variable, then:
- Independent Variable: Time of day when brushing (e.g., morning vs. night)
- Dependent Variable: Whiteness of teeth
- Control: Toothpaste used, brushing duration, pressure, etc.

But since Brock used two different toothpastes, it's likely the toothpaste is the real IV.

✔ Best Answer Based on Description:
- Independent Variable: Type of toothpaste
- Dependent Variable: Whiteness of teeth
- Control: Brushing habits, diet, frequency, etc.

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Scenario 3:

> Chloe wants to see if the food plants grow better in full sunlight or partial sunlight. She plants 5 basil plants on the west side of her house that only receives light in the morning, and 5 more plants on the east side of her house that receives light all day. After 2 months Chloe measures the height of each plant.

- Independent Variable: Amount of sunlight (full sunlight vs. partial sunlight)
- Dependent Variable: Height of the plants
- Control: Type of plant (basil), soil, water, temperature, pot size, etc.

✔ Answer:
- Independent Variable: Sunlight exposure (full vs. partial)
- Dependent Variable: Height of plants
- Control: Plant type, soil, watering schedule, etc.

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Scenario 4:

> Mela wants to see if the amount of fertilizer used affects plant growth. She puts no fertilizer on the first plant, half a cup on the second, and a full cup on the third. All plants are placed in the same room and get the same amount of sunlight and water. After three weeks Mela measures the plant's growth.

- Independent Variable: Amount of fertilizer (none, half cup, full cup)
- Dependent Variable: Plant growth (measured by height or size)
- Control: Light, water, room temperature, plant type, soil, pot size, etc.

✔ Answer:
- Independent Variable: Amount of fertilizer
- Dependent Variable: Plant growth
- Control: Light, water, temperature, soil, etc.

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Scenario 5:

> Evan wants to see if a black crayon works better than a colored crayon. He makes a set of marks on paper using both crayons, and then uses a ruler to measure the length of each mark. He records the data.

- Independent Variable: Type of crayon (black vs. colored)
- Dependent Variable: Length of the mark made
- Control: Pressure applied, surface of paper, hand strength, drawing technique, etc.

✔ Answer:
- Independent Variable: Type of crayon
- Dependent Variable: Length of the mark
- Control: Drawing method, paper, force used, etc.

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✔ Final Answers Summary:

| Scenario | Independent Variable | Dependent Variable | Control |
|--------|----------------------|--------------------|---------|
| 1 | Size of the seed | Growth rate of the plant | Water, sunlight, soil, temperature |
| 2 | Type of toothpaste | Whiteness of teeth | Brushing habits, diet, frequency |
| 3 | Sunlight exposure (full vs. partial) | Height of plants | Plant type, soil, water, etc. |
| 4 | Amount of fertilizer | Plant growth | Light, water, temperature, soil |
| 5 | Type of crayon (black vs. colored) | Length of the mark | Pressure, paper, drawing technique |

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🔍 Explanation of Variables:

- Independent Variable (IV): The factor that the experimenter deliberately changes.
- Dependent Variable (DV): The outcome that is measured; it depends on the IV.
- Control: The factors that are kept constant so they don’t affect the results.

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