Falling Objects
Scientists tend to be very curious about certain phenomena around them. Falling objects is one
of these phenomena that has raised up a lot of reflection and experimentation among
scientists.
Aristotle’s Hypothesis about falling objects:
If the object is heavier, then it will fall more quickly.
A mass of 10 Kg will fall twice as fast as a mass of 5 Kg.
Aristotle was a Greek philosopher. He thought deeply but
he did not feel the need to test his hypothesis.
Aristotle 384-322 BCE
Galileo’s hypothesis about falling objects:
If the object is heavier, then it will not fall faster.
The motion of falling bodies should be independent of its
weight. If they are the same shape they will fall at the
same time.
Galileo Galilei 1564-1642
Galileo was a renowned Italian scientist who disagreed
with Aristotle. According to legend he tested his
reasoning experimentally by dropping cannon balls and
bullets off the Leaning Tower of Pisa.
Sir Isaac Newton, a British Physicist and Mathematician,
describes the Theory of Gravity in 1687
2000 years after Aristotle and 35 years after Galileo
Gravitational attraction depends on the mass of the two
objects and the distance between them.
Sir Isaac Newton1623-1747
Problem:

Does the mass of a falling object influence the time of the objects free fall?

What other factors influence the time of 2 objects falling from the same height?
Hypotheses:

If a golf ball and a tennis ball are dropped from the same height, then
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
Two pieces of tin foil are of the same mass; one is flat, the other rolled into a ball. If they
are dropped from the same height, then
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Material:
Procedure:
Data: Table 1: Mass of objects
Objects 
Mass
Golf ball
Ping pong ball
Tin foil ball
Tin foil sheet
Table 2: Time of falling objects at 1 meter and 5 meters
Objects
Golf ball
Ping Pong
ball
Tin foil
ball
Tin foil
sheet
Time (sec) 1meter
Trial 1 Trial 2
Trial 3
average
Time (sec) 5 meters
Trial 1
Trial 2
Trial 3
average
Table 3: Reaction error for stop watch
15sec
Lowest
Highest
+/- range
Analysis:
1. Compare the falling time for the three balls. Do your results of your experiment support your
hypothesis concerning the time of falling bodies?
2. Compare the falling times for the foil ball and foil sheet. Do your results support your second
hypothesis?
Conclusion:
3. What Factors influence the time of falling bodies?
4. What is the relationship between the time of falling bodies and their mass?
5. Your reaction time with the stop watch is a source of error. Give two ways to compensate for
that error.
6. Newton said Gravitational attraction between 2 objects depends on the mass of the objects
and the distance separating them. Galileo said that 2 object would fall at the same time even if
they had a different mass. Explain how Newton’s theory supports Galileo’s findings.