These gravity experiments are all fantastic demonstrations of gravity and a great way to learn about Isaac Newton and Galileo’s famous discoveries. If you enjoy them, do check our my book This IS Rocket Science which is full of exciting space activities demonstrating how rockets overcome gravity and other forces to launch into space followed by a tour of the solar system with an activity for each planet before bringing you back down to Earth with a bump.
What is Gravity?
Gravity is the force that pulls objects towards the Earth. It’s the reason we walk on the ground rather than float around.
Gravity also holds Earth and the other planets in their orbits around the Sun.
Did you know – gravity also exists on the Moon but it is not as strong as on Earth, which is why astronauts can jump higher on the Moon than on Earth. This article from ScienceAlert tells you how high you could jump on each planet in the Solar System compared to Earth.
Great Gravity Experiments
Galileo and Gravity
Galileo was a famous scientist in the 16th and 17th Century. His most famous observation was that two objects of the same size but different weights hit the ground at the same time if they are dropped from the same height. This happens because the force of gravity acting on both objects is the same.
If a feather and a ball are dropped from the same height ( on Earth ) they fall at different rates. This is because the feather has more air resistance acting on it. Air pressure acts on the feather from all directions counteracting the force of gravity.
Galileo dropped two balls of different weights but the same size off the Leaning Tower of Pisa, proving that the weight of an object doesn’t affect how fast it falls.
However if a ball and feather are dropped in a vacuum, where there is no air resistance as there’s no air, the ball and feather will hit the ground at the same rate.
Bottle Drop Experiment
Following on from the ball and feather experiment another great example of Galileo’s discovery is to half fill one plastic bottle and leave another ( the same size ) empty. If dropped from the same height they will hit the ground at the same time!
Issac Newton and Gravity
According to legend Issac Newton was sitting under an apple tree when an apple fell on his head, which made him wonder why if fell to the ground.
Newton published the Theory of Universal Gravitation in the 1680s, setting forth the idea that gravity was a force acting on all matter. His theory of gravity and laws of motion are some of the most important discoveries in science and have shaped modern physics.
Film Canister Rocket
Water powered bottle rockets are another great fun example of gravity and lots of other forces too!
Defy gravity with a magnet
Did you know you can defy gravity using magnets. We love this activity as you can theme it however you want. Your floating object could be a spaceship in space, a flower growing towards the sun or even a plane in the sky.
Straw Rockets – Gravity Experiment
Create your own straw rockets and launch at different angles to investigate how the trajectory changes. Of course these don’t have to be rockets, they could be anything you want, so get creative!