Variables exercise - Free Printable
Educational worksheet: Variables exercise. Download and print for classroom or home learning activities.
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Show Answer Key & Explanations
Step-by-step solution for: Variables exercise
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Show Answer Key & Explanations
Step-by-step solution for: Variables exercise
Let's go through each item and identify the Independent Variable (I), Dependent Variable (D), and Constants (C).
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- Independent Variable (I): The factor that is deliberately changed or manipulated by the experimenter.
- Dependent Variable (D): The outcome that is measured or observed; it depends on the independent variable.
- Constants (C): Factors that are kept the same throughout the experiment to ensure a fair test.
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Now, let’s solve each one:
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1. A study was done to find if different tire treads affect the braking distance of a car.
- I: Type of tire tread
- D: Braking distance
- C: Car model, speed, road conditions, driver, weight of car, brake condition
> *Explanation:* The researcher changes the tire tread (I), then measures how far the car travels before stopping (D). Other factors must remain constant to isolate the effect of the tread.
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2. The time it takes to run a mile depends on the person’s running speed.
- I: Running speed
- D: Time to run a mile
- C: Distance (1 mile), terrain, weather, runner’s health/condition (assumed consistent)
> *Explanation:* Speed is varied, and time is measured. Distance is fixed at 1 mile — this is a constant.
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3. The height of bean plants depends on the amount of water they receive.
- I: Amount of water
- D: Height of bean plants
- C: Type of plant, soil type, sunlight, temperature, pot size, amount of fertilizer
> *Explanation:* Water amount is manipulated; plant height is measured. All other growing conditions should be controlled.
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4. The higher the temperature of the air in the oven, the faster a cake will bake.
- I: Oven temperature
- D: Baking time (or speed of baking)
- C: Recipe (amount of ingredients), oven type, cake size, altitude, humidity
> *Explanation:* Temperature is changed; how fast the cake bakes is observed. Other aspects of the cake and oven setup stay the same.
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5. Lemon trees receiving the most water produced the most lemons.
- I: Amount of water
- D: Number of lemons produced
- C: Type of lemon tree, sunlight, soil quality, fertilizer, pests, climate
> *Explanation:* Water amount is varied; fruit yield is measured. Other environmental and biological factors should be held constant.
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6. An investigation found that more bushels of potatoes were produced when the soil was fertilized more.
- I: Amount of fertilizer
- D: Bushels of potatoes produced
- C: Soil type, amount of water, sunlight, planting depth, potato variety, pest control
> *Explanation:* Fertilizer level is changed; potato yield is measured. Other growing conditions are kept constant.
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7. Students measured the temperature of the water at different depths in Lake Skywalker and found that the temperature varied.
- I: Depth of water
- D: Water temperature
- C: Location in lake, time of day, season, weather conditions
> *Explanation:* Depth is what is being tested; temperature is the result. Other external variables should be constant.
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8. The amount of pollution produced by cars was measured for cars using gasoline containing different amounts of lead.
- I: Amount of lead in gasoline
- D: Amount of pollution produced
- C: Car model, engine size, driving conditions, speed, distance driven, fuel efficiency
> *Explanation:* Lead content in fuel is varied; pollution output is measured. Cars and driving conditions are kept consistent.
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9. Four groups of rats are first massed and then fed identical diets except for the amount of vitamin A they receive. Each group gets a different amount. After 3 weeks on the diet, the rats’ masses are measured again to see if there has been a decrease.
- I: Amount of vitamin A in diet
- D: Change in mass of rats (or final mass)
- C: Diet (except vitamin A), initial mass, age, environment, cage conditions, duration of feeding, water intake
> *Explanation:* Vitamin A amount is manipulated; change in body mass is the response. All other dietary and environmental factors are kept the same.
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| Item | I | D | C |
|------|---|---|---|
| 1 | Type of tire tread | Braking distance | Car model, speed, road conditions, etc. |
| 2 | Running speed | Time to run a mile | Distance (1 mile), terrain, weather |
| 3 | Amount of water | Height of bean plants | Soil, sunlight, temperature, pot size |
| 4 | Oven temperature | Baking time | Recipe, cake size, oven type |
| 5 | Amount of water | Number of lemons | Tree type, sunlight, soil, fertilizer |
| 6 | Amount of fertilizer | Bushels of potatoes | Soil type, water, sunlight, variety |
| 7 | Depth of water | Water temperature | Location, time, season |
| 8 | Amount of lead in gasoline | Amount of pollution | Car model, driving conditions |
| 9 | Amount of vitamin A | Change in rat mass | Diet (except vitamin A), initial mass, environment |
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🔹 Definitions:
- Independent Variable (I): The factor that is deliberately changed or manipulated by the experimenter.
- Dependent Variable (D): The outcome that is measured or observed; it depends on the independent variable.
- Constants (C): Factors that are kept the same throughout the experiment to ensure a fair test.
---
Now, let’s solve each one:
---
1. A study was done to find if different tire treads affect the braking distance of a car.
- I: Type of tire tread
- D: Braking distance
- C: Car model, speed, road conditions, driver, weight of car, brake condition
> *Explanation:* The researcher changes the tire tread (I), then measures how far the car travels before stopping (D). Other factors must remain constant to isolate the effect of the tread.
---
2. The time it takes to run a mile depends on the person’s running speed.
- I: Running speed
- D: Time to run a mile
- C: Distance (1 mile), terrain, weather, runner’s health/condition (assumed consistent)
> *Explanation:* Speed is varied, and time is measured. Distance is fixed at 1 mile — this is a constant.
---
3. The height of bean plants depends on the amount of water they receive.
- I: Amount of water
- D: Height of bean plants
- C: Type of plant, soil type, sunlight, temperature, pot size, amount of fertilizer
> *Explanation:* Water amount is manipulated; plant height is measured. All other growing conditions should be controlled.
---
4. The higher the temperature of the air in the oven, the faster a cake will bake.
- I: Oven temperature
- D: Baking time (or speed of baking)
- C: Recipe (amount of ingredients), oven type, cake size, altitude, humidity
> *Explanation:* Temperature is changed; how fast the cake bakes is observed. Other aspects of the cake and oven setup stay the same.
---
5. Lemon trees receiving the most water produced the most lemons.
- I: Amount of water
- D: Number of lemons produced
- C: Type of lemon tree, sunlight, soil quality, fertilizer, pests, climate
> *Explanation:* Water amount is varied; fruit yield is measured. Other environmental and biological factors should be held constant.
---
6. An investigation found that more bushels of potatoes were produced when the soil was fertilized more.
- I: Amount of fertilizer
- D: Bushels of potatoes produced
- C: Soil type, amount of water, sunlight, planting depth, potato variety, pest control
> *Explanation:* Fertilizer level is changed; potato yield is measured. Other growing conditions are kept constant.
---
7. Students measured the temperature of the water at different depths in Lake Skywalker and found that the temperature varied.
- I: Depth of water
- D: Water temperature
- C: Location in lake, time of day, season, weather conditions
> *Explanation:* Depth is what is being tested; temperature is the result. Other external variables should be constant.
---
8. The amount of pollution produced by cars was measured for cars using gasoline containing different amounts of lead.
- I: Amount of lead in gasoline
- D: Amount of pollution produced
- C: Car model, engine size, driving conditions, speed, distance driven, fuel efficiency
> *Explanation:* Lead content in fuel is varied; pollution output is measured. Cars and driving conditions are kept consistent.
---
9. Four groups of rats are first massed and then fed identical diets except for the amount of vitamin A they receive. Each group gets a different amount. After 3 weeks on the diet, the rats’ masses are measured again to see if there has been a decrease.
- I: Amount of vitamin A in diet
- D: Change in mass of rats (or final mass)
- C: Diet (except vitamin A), initial mass, age, environment, cage conditions, duration of feeding, water intake
> *Explanation:* Vitamin A amount is manipulated; change in body mass is the response. All other dietary and environmental factors are kept the same.
---
✔ Final Answers:
| Item | I | D | C |
|------|---|---|---|
| 1 | Type of tire tread | Braking distance | Car model, speed, road conditions, etc. |
| 2 | Running speed | Time to run a mile | Distance (1 mile), terrain, weather |
| 3 | Amount of water | Height of bean plants | Soil, sunlight, temperature, pot size |
| 4 | Oven temperature | Baking time | Recipe, cake size, oven type |
| 5 | Amount of water | Number of lemons | Tree type, sunlight, soil, fertilizer |
| 6 | Amount of fertilizer | Bushels of potatoes | Soil type, water, sunlight, variety |
| 7 | Depth of water | Water temperature | Location, time, season |
| 8 | Amount of lead in gasoline | Amount of pollution | Car model, driving conditions |
| 9 | Amount of vitamin A | Change in rat mass | Diet (except vitamin A), initial mass, environment |
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Let me know if you'd like this formatted as a printable worksheet!
Parent Tip: Review the logic above to help your child master the concept of variables worksheet answers.
