What Did Galileo Discover About Gravity?

Galileo discovered that all objects fall at the same rate, no matter how heavy or light they are, if we ignore air resistance.

What Galileo Discovered

Galileo found that when air resistance is removed (like in a vacuum), all objects fall at the same rate—no matter their weight or size.

For example:

• If you drop a feather and a rock in a vacuum (no air), they both hit the ground at the same time.

What the Principle Says:

All objects fall with the same constant acceleration due to gravity,

which on Earth is about 9.8 m/s² (meters per second squared).

This means:

• Each second, an object speeds up by 9.8 meters per second.

• A heavier object does not fall faster than a lighter one, as people used to believe before Galileo.

Why This Was Important

Before Galileo, people believed heavier things fall faster.

But Galileo tested this by:

• Dropping different objects from the Leaning Tower of Pisa (according to legend).

• Rolling balls of different weights down ramps and timing them.

He proved:

• Mass doesn’t affect how fast something falls (if no air slows it down).

• Only gravity pulls them, and gravity pulls everything equally.

How did he find it out?

1. Rolling Balls Down Ramps

Instead of dropping things straight down, Galileo used inclined planes (ramps).

Why? Because falling happens too fast to measure easily, but rolling slows things down so he could observe carefully.

• He rolled balls of different masses down smooth ramps.

• He measured how far they rolled in certain time intervals.

• He discovered that they all sped up at the same rate—no matter how heavy they were.

2. Careful Timing (Using Water Clocks or Pendulums)

Galileo didn’t have stopwatches.

So he used:

• Water clocks (letting water drip into a container).

• Pendulums (he discovered they swing in regular patterns).

These helped him measure time very accurately.

3. Observing Falling Objects (Possibly from Pisa Tower)

There’s a famous story (we don’t know for sure if it really happened) that he dropped:

• A light ball and a heavy ball from the Leaning Tower of Pisa.

• Both hit the ground at the same time.

This showed that weight doesn’t change how fast something falls—air resistance was the only thing that made lighter things fall slower, like feathers.

Conclusion

Galileo used:

• Clever experiments (ramps and timing)

• Careful observations

• Logical thinking

He proved something that no one believed before him:

Gravity pulls everything equally, no matter how big or small.