Please answer the following by identifying the variables in each problem (independent variable, dependent variable, and controlled variable). Read each problem carefully.

1. Problem: How does the amount of water affect the height of bean plants over two weeks?
- IV (Independent Variable) –
- DV (Dependent Variable) –
- CV (Controlled Variable) –

2. Problem: What is the effect of different light durations on the number of leaves produced by sunflowers within a month?
- IV –
- DV –
- CV –

3. Problem: How does the duration of exercise impact the heart rate of individuals aged 12–14?
- IV –
- DV –
- CV –

4. Problem: What is the relationship between the type of insulation and the time it takes for ice to melt in different environments?
- IV –
- DV –
- CV –

5. Problem: How do different types of fertilizers affect the growth of tomato plants over four weeks?
- IV –
- DV –
- CV –

6. Problem: What is the impact of listening to different genres of music on the concentration levels of students during a 30-minute study session?
- IV –
- DV –
- CV –

7. Problem: How does the salinity of water influence the growth of lettuce plants over three weeks?
- IV –
- DV –
- CV –

8. Problem: What factors affect the distance traveled by paper airplanes when launched indoors?
- IV –
- DV –
- CV –

9. Problem: How does the type of surface impact the bounce height of rubber balls when dropped from the same height?
- IV –
- DV –
- CV –

10. Problem: How does varying the cooking time affect the texture of chocolate cakes using the same recipe?
- IV –
- DV –
- CV –

11. Problem: What is the relationship between the strength of magnets and the number of paper clips attracted in a controlled environment?
- IV –
- DV –
- CV –

12. Problem: How does the amount of salt added affect the boiling point of water during a cooking experiment?
- IV –
- DV –
- CV –

13. Problem: What is the impact of different brands of paper towels on their absorbency when cleaning up a fixed amount of liquid?
- IV –
- DV –
- CV –

14. Problem: How does the type of soil influence the height of marigold plants over a month?
- IV –
- DV –
- CV –

15. Problem: What is the effect of temperature on the rate of crystallization in a saturated solution?
- IV –
- DV –
- CV –

16. Problem: How does the distance from a sound source affect the intensity of the sound measured using a sound meter?
- IV –
- DV –
- CV –

17. Problem: What is the impact of different types of soap on the surface tension of water using identical containers?
- IV –
- DV –
- CV –

18. Problem: How does the length of a pendulum influence the time it takes to complete one full swing in a controlled environment?
- IV –
- DV –
- CV –

19. Problem: What is the correlation between the pH level of soil and the health of cucumber plants over a growth period?
- IV –
- DV –
- CV –

20. Problem: How do different liquids impact the rate of evaporation when exposed to the same environmental conditions?
- IV –
- DV –
- CV –

21. Problem: How does the time spent reading affect the memory retention of middle school students?
- IV –
- DV –
- CV –

22. Problem: What is the relationship between air pressure and the size of balloons when inflated in a controlled setting?
- IV –
- DV –
- CV –

23. Problem: How does the type of paper affect the absorption of ink when using different writing instruments?
- IV –
- DV –
- CV –

24. Problem: How does the water temperature influence the diffusion rate of food coloring in a controlled environment?
- IV –
- DV –
- CV –

25. Problem: What is the impact of humidity levels on the longevity of curls produced using a curling iron?
- IV –
- DV –
- CV –

26. Problem: How does the wind speed affect the duration and height of kite flight using the same type of kite?
- IV –
- DV –
- CV –

27. Problem: What is the effect of different brands of soap on the size of soap bubbles produced using identical bubble wands?
- IV –
- DV –
- CV –

28. Problem: How does the amount of water influence the germination rate of sunflower seeds in a controlled environment?
- IV –
- DV –
- CV –

29. Problem: What is the correlation between the type of battery and the brightness of a flashlight during a fixed time period?
- IV –
- DV –
- CV –

30. Problem: How does the surface type affect the speed of toy cars when released from the same height?
- IV –
- DV –
- CV –

The independent variable (IV) is what is being changed or manipulated in an experiment, the dependent variable (DV) is what is being observed or measured, and the controlled variable (CV) is what is kept constant throughout the experiment. The specific variables for each problem are provided in the formatted detailed answer.

In each problem, there are three types of variables: independent variable (IV), dependent variable (DV), and controlled variable (CV).

1. The IV is the amount of water, the DV is the height of bean plants, and the CV could be the type of soil, amount of sunlight, and temperature.

2. The IV is the light duration, the DV is the number of leaves produced by sunflowers, and the CV could be the type of soil, amount of water, and temperature.

3. The IV is the duration of exercise, the DV is the heart rate of individuals aged 12-14, and the CV could be the type of exercise, time of day, and rest periods between exercises.

4. The IV is the type of insulation, the DV is the time it takes for ice to melt, and the CV could be the type of ice, temperature, and humidity.

5. The IV is the type of fertilizers, the DV is the growth of tomato plants, and the CV could be the type of soil, amount of water, and sunlight.

6. The IV is the different genres of music, the DV is the concentration levels of students, and the CV could be the time of day, noise level, and study environment.

7. The IV is the salinity of water, the DV is the growth of lettuce plants, and the CV could be the type of soil, amount of water, and temperature.

8. The IV is factors affecting the distance traveled by paper airplanes, the DV is the distance traveled by paper airplanes, and the CV could be the type of paper airplane, launch method, and air resistance.

9. The IV is the type of surface, the DV is the bounce height of rubber balls, and the CV is the height from which the balls are dropped.

10. The IV is the cooking time, the DV is the texture of chocolate cakes, and the CV is the recipe, type of oven, and temperature.