Have your ever wondered what pulls you back to the ground when you jump, or why a ball always lands on the ground after you throw it? Well, the great scientist Sir Isaac Newton wondered about this too. Newton is famous for several incredible things however he is most well-known for creating the theory of universal gravity.
Around 1666, legend has it that after watching an apple fall from the tree, he realised that there had to be something pulling that apple to the ground and he wanted to understand what it was. Other scientists had thought about this before of course and had also made some great discoveries. Galileo discovered that dropping two objects from the same height would result in them hitting the ground at the same time, no matter their difference in weight. However, there can’t really be any air resistance. If you drop a feather and a bowling ball at the same time, the bowling ball will always hit the ground first… unless all the air is taken out of the room! This experiment shows that the force pulling the two objects to the ground is the same. To see this yourself, drop a half-filled water bottle and one empty water bottle, both the same size, from the same height. They will land on the ground at the same time.
Newton’s curiosity alongside his intelligence meant that after years of thinking about gravity, he developed some amazing new theories of his own. He even used maths to complete calculations on gravity that supported these theories. This math showed how invisible gravity worked and also provided a possible explanation as to the whole shape of our universe.
Newton wrote that gravity was the force pulling two masses together and that it applied to objects of all sizes. The larger an object was, the more it attracted other objects. Up until this point, nobody could really explain how the orbits of the planets and moon worked…although they definitely tried and came up with some interesting ideas. Thanks to Newton, people began to understand that gravitational pull (or attraction) is the reason why planets orbit the Sun and don’t simply fly off into space. Even the Earth’s moon orbits Earth perfectly without being sling shotted into the galaxy! This, along with many other reasons, makes gravity extremely important to us and helps our world function the way it does.
The moon’s surface gravity is weaker because it is not as massive as Earth and is only about 60% as dense. That’s why astronauts appear to bounce when they’re on the moon and why people weigh less on it. If you weigh 60 kilograms on Earth, you would weigh about 10 kilograms on the moon!
Understanding the Effects of Gravity
Gravity is a force that we feel and experience every single day of our lives. Although we cannot see gravity, we can see the effect it has. For example, it is what makes round objects roll down a hill and it is what makes a glass shatter when you drop it. Engino’s Inertia, Momentum, Kinetic and Potential Energy kit makes understanding gravity, as well as the basics of physics and mechanics, easy. You can construct different objects and witness yourself how gravity affects them, plus so much more.
You can find more fun gravity experiments here.
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Learn about Isaac Newton’s life and scientific discoveries with this awesome book.