Final answer:
The independent variable in Terri's experiment is the size of the ball, as she uses balls of different sizes to see their effect on the ball's instantaneous and average speed. In a similar experimental context, to show that acceleration is independent of velocity, a student needs to measure initial speeds and the time each ball takes to reach the ground. Differences observed in Jaiqua and Harold's experiment are possibly due to interobserver variability.
Step-by-step explanation:
Terri's independent variable in her experiment is the size of the ball. She is investigating if this variable affects the ball's instantaneous and average speed. An independent variable is the one that is changed or controlled in a scientific experiment to test the effects on the dependent variable. In Terri's case, she uses a tennis ball, softball, and basketball, each with different sizes, and rolls them down the same ramp to measure their speeds. To accurately gauge the impact of the ball size on its speed, she would measure the time it takes each ball to travel a set distance and use these times to calculate their speeds.
For a student wishing to design an experiment to show that the acceleration of an object is independent of the object's velocity, they would need to collect several types of data. They would need the initial speed for the balls that are launched and the time it takes for each ball to reach the ground. This would allow for the calculation of acceleration and to compare it between the different velocities of the balls at the start of their movements. The hypothesis is that regardless of the initial velocity, the acceleration due to gravity for each ball will be the same.
For Jaiqua and Harold, the differences in outcomes when measuring the time it takes for a ball to roll down ramps with different slopes may be attributed to interobserver variability. This is the inconsistency that can occur due to individual differences between observers measuring the same events, such as reaction times when using a stopwatch.
When designing an experiment, it's crucial to repeat the process with different individuals performing the tasks of experimenter, timer, and recorder to identify any potential discrepancies that may be due to this type of variability and not the experimental conditions themselves. Only by controlling for such variability can the experimenters ensure that the data reflects the true nature of the phenomena being studied.