Question 32

The scientist is using a controlled experiment.

In this investigation, the scientist systematically varies the speed of the water while measuring the size of sediment particles carried away. This method clearly indicates that a controlled experiment is being conducted, as the scientist is manipulating one variable to observe its effect on another.

A) Observational study

An observational study involves observing subjects without manipulation of variables. In this case, the scientist is actively changing the speed of the water and measuring the outcome, which disqualifies this option as correct.

B) Controlled experiment

This is the correct choice because the scientist is manipulating a single variable (the speed of water) to observe its effect on the size of sediment particles. This approach allows for a clear cause-and-effect relationship to be established.

C) Computational model

A computational model uses simulations to predict outcomes based on input data. The scientist in this scenario is conducting physical measurements and observations directly rather than relying on a computational approach, making this option incorrect.

D) Field study

A field study typically involves observing and collecting data in a natural environment without controlled conditions. Since the scientist is controlling and varying the water speed in a defined setup, this option does not accurately describe the investigation.

Conclusion

The investigation is classified as a controlled experiment because the scientist manipulates the speed of the water to observe its effect on sediment particle size. Other options, such as observational study, computational model, and field study, do not involve the same level of experimental control and direct manipulation of variables, making them incorrect in this context.