Exploring Gravity Lab Directions
(Please Write All Answers/Data on Student Answer Sheet)
Objective:
The goal of this experiment is to repeat Galileo's famous experiment to answer the question
“do heavier objects fall faster than lighter ones?”
Background Information:
In 1589, a young scientist and mathematician named Galileo Galilei conducted a simple
experiment. Galileo stood on a balcony near the top of the 179-foot tall Tower of Pisa and
dropped two iron balls of different masses from a great height to see which ball hit the
ground first. The scientist was not trying to knock his fellow professors on the head, but was
trying to prove his theory that all objects fall to earth at the same rate, regardless of their
mass.
This experiment challenged a 2000 year-old idea proposed by the philosopher Aristotle, who
believed that heavier objects fall faster than lighter objects. Aristotle thought that a ball that
was 10 times as heavy as another ball would fall 10 times as fast. Neither Aristotle nor any one
else had ever tested to see if his idea was correct.
Galileo proved Aristotle wrong when he dropped a 10 pound ball and a 1 pound ball from
the top of the Leaning Tower of Pisa, and a crowd watched them hit the ground at the
same time. Galileo's experiment showed that experimentation is necessary to test scientific
theories.
In this experiment, you will repeat Galileo's experiment while standing on a chair to see if you
get the same results. Look out below!
Terms and Concepts:
 Galileo, motion, gravity, mass, air resistance, inertia and acceleration
Materials and Equipment:
 Two balls of the same size, but different masses
 Two pieces of paper of the same size, but different masses
Experimental Procedure (You must work with at least one other person to accurately record
data):
1. Stand on a chair and drop both balls from the same height at the same time (other group
members check to see which ball hit first or if they hit at the same time)
2. Check off which ball hit first in your data table (or same time)
3. Do this 5 times to be sure that your results are consistent
4. Next, repeat the experiment with pieces of paper of two different masses and record the
results in the 2nd data table.
5. After you have done the experiment, try balling up the pieces of paper and dropping
them. Did they fall at the same rate?
Name:_____________________________________
Date:______________________________________
Exploring Gravity Lab: Student Answer Sheet
Hypothesis:_______________________________________________________________________________
__________________________________________________________________________________________
Identification of Variables (re-read the objective to help you with this part):
Balls of Different Masses:
Independent Variable:___________________________________________________________________
Dependent Variable:_____________________________________________________________________
Experimental Group:______________________________________________________________________
Control Group:___________________________________________________________________________
Contants:________________________________________________________________________________
Pieces of Paper with Different Masses:
Independent Variable:___________________________________________________________________
Dependent Variable:_____________________________________________________________________
Experimental Group:______________________________________________________________________
Control Group:___________________________________________________________________________
Contants:________________________________________________________________________________
Data Table
Trial #
Heavy
Ball
Light
Ball
Data Table
Same
Time
Trial #
Heavy
Paper
Light
Paper
Same
Time
Discussion Questions:
1. What force causes all objects to fall to the ground and where does this force come from?
2. What affect does air resistance have on falling objects?
3. Did balling up the paper have an effect on how fast it fell? Why or why not (refer to your
answer in #2)?
4. What do you think would happen if you performed the same experiment in a vacuum,
which has no air in it?
5. Using the term inertia, discuss which of Galileo’s balls used in the experiment, the 10lb or
the 1lb would cause the worst injury to someone standing below if it were to hit them on
the head.
6. Describe how you think the human body has adapted to the force of gravity on Earth over
time. How might it have evolved if gravity had not been present?
7. Which of Newton’s laws of motion involve the force of gravity? Give examples of each law
of motion that occurs in your everyday life.