Galileo Galilei dropped objects of different masses from the Leaning Tower of Pisa to determine if heavier objects fall faster, finding that a cannonball and feather reached the ground at the same time, establishing the principle of universal free fall. This demonstrated that gravity exerts the same downward acceleration on all objects regardless of their mass or composition.

1. Universality of Free Fall

2. I wonder…
 Would an object that weighs 10X more fall 10X
faster?
 If you had a golf ball and a bowling ball, and
dropped them from a high building, which one do
you think would land first?

3.  Galileo Galilei was an Italian mathematician,
astronomer, and philosopher. About four hundred
years ago (1630) -- or so the story goes – he started
dropping things off the Leaning Tower of Pisa…

4.  He dropped
objects of
different weights,
sizes, and
materials-
Cannon balls,
musket balls,
gold, silver and
wood.
 He wanted to
find out which
objects fell
faster. Which
objects do you
think landed

5.  Galileo Galilei found
that all the objects hit
the ground at the
same time, no matter
how heavy they
were!
 ...and so he made a
big discovery: gravity
places the same
amount of force on
all objects,
regardless of how
heavy they are
(mass) or what they
are made of
(composition).

6. Nowadays this is called "Universality of
Free Fall" or the "Equivalence
Principle”.

7. If I drop a book or a piece
of paper, which do you
think would land first?
 Air resistance (like a parachute)