EXPERIMENT 7.1

ACCELERATION DUE TO GRAVITY

Student Information:

PURPOSE:

To observe how acceleration due to gravity is independent of the object falling.

MATERIALS:

SAFETY:

  • Always wear eye protection when dropping objects.
  • Make sure the area below is clear of obstacles and people.
  • Be careful when handling heavy books to avoid injury.

BACKGROUND:

One of the properties of free fall is that all objects experience the same acceleration regardless of their weight or physical makeup. That tends to go against your everyday experience. This experiment shows you that it is, indeed, true.

In the absence of air resistance, all objects fall at the same rate under the influence of gravity. This is because the acceleration due to gravity (approximately 9.8 m/s²) acts equally on all objects regardless of their mass. The force of gravity is proportional to an object's mass, but the acceleration produced is independent of mass because the greater force on a more massive object is offset by its greater inertia.

However, in the real world, air resistance can significantly affect the motion of falling objects, especially those with large surface areas relative to their mass. This experiment will demonstrate both scenarios: objects falling with and without the influence of air resistance.

QUESTION:

What happens when you drop two different objects at the same time? Do they hit the ground simultaneously?

HYPOTHESIS:

Write what you predict will happen to the paper and the book when dropped from the same height at the same time. Will they hit the ground together, or will one hit before the other?

PROCEDURE:

  1. Hold the book in one hand and the paper in the other. Hold both of them out at arm's length, and make sure that they are at exactly the same height. Make sure that there are no obstructions beneath the two objects so that they can fall to the floor without running into something.

  2. Now, release them both at precisely the same instant. Note what happens. Specifically, note which object (the book or the paper) hits the ground first. If they hit simultaneously, note that.

  3. Next, repeat the experiment in a slightly different way. This time place the piece of paper on top of the book and hold the book out at arm's length with both hands. Now release the book and paper. Note what happens this time.

VIDEO DEMONSTRATION:

Watch this demonstration of the gravity experiment to see the concepts in action:

What to Look For:

  • Notice how objects fall when dropped together vs. separately
  • Observe the effect of air resistance on different objects
  • Pay attention to the timing of when objects hit the ground
  • Consider how this demonstrates the principles of gravity

Alternative Link: If the video doesn't load, you can watch it directly at: https://www.youtube.com/shorts/X5uKz67suXs

ANALYSIS QUESTIONS:

1. In the first trial, which object hit the ground first? Why do you think this happened?

2. In the second trial, did the paper and book hit the ground at the same time? Explain why.

3. What force caused the difference in results between the two trials?

4. If you were to perform this experiment on the Moon (which has no atmosphere), how would the results differ from what you observed on Earth?

5. How does this experiment demonstrate Newton's Second Law of Motion?

CONCLUSION:

Write a paragraph about what happened in the two trials you performed. Make connections to the text (specifically the paragraphs that follow).

EXTENSION:

Try this experiment with different objects of varying weights and shapes. How does air resistance affect the falling rate of different objects? Can you design an object that falls more slowly than a flat piece of paper?

SUBMIT YOUR RESULTS:

Click the button below to submit your experiment results to your teacher.