Galileo Galilei

Galileo Galilei

Father of modern physics

Ambitious, unconventional and rebellious, Galileo was a brilliant and ground-breaking scientist.

Famous for:

1. Supporting the Copernican theory that the Sun is the centre of the Universe and that all the planets orbit it. This got him into trouble with the Roman Catholic Church, which banned Galileo from teaching.

2. Discovering Jupiter's four biggest moons.

Jupiter and moon_ST002424

Jupiter and one of its moons

3. Realising that pendulums swing at a steady rate and can be used to make accurate clocks. How do you time a pendulum without a stopwatch? Do what Galileo did, use your pulse.

Pendulum clock_100416432

Galileo discovered that pendulums can be used to make clocks

Fun fact:

  • On the same day that Galileo died, Isaac Newton was born. What a coincidence! Newton went on to use Galileo's ideas to completely change our view of the universe.

Be Galileo!

You can recreate one of his experiments. Galileo showed that if you drop objects that are the same shape from a height they hit the ground at the same time, even if one object is heavier than the other.

Try it out! Gather balls of different sizes and weights - try footballs, tennis balls and ping pong balls. Stand on a chair and hold your a ball in each hand, with your arms outstretched. Drop the balls at the same time.

What do you notice? The balls should hit the ground at the same time. The force of gravity acting on both balls is the same, even though they are different weights.

What if you try this with a feather and a ball?

Repeat the experiment with a feather and a tennis ball. What do you notice? The tennis ball should hit the ground first. Why? The force of gravity acting on the ball and the feather is the same, but the feather experiences more air resistance.

What would happen if you tried it in a vacuum?

Astronaut David Scott tried it out - on the moon! He dropped a hammer and a feather at the same time.

Watch this video to see what happened:

The hammer and feather hit the ground at the same time! There is no air on the moon - it is a vacuum. This means that there is no air resistance. However, gravity is still present. The experiment shows that the force of gravity acting on both objects is the same, regardless of their weight.