Have you ever wondered why when we drop objects, all things touchdown eventually ? If so, how can birds and airplanes fly? Why do some objects seem to fall faster than others? Would you like to lose a tiny bit of weight and live longer? Did you know, by the end of the day your height shrinks a little, too? What keeps planets and moons in their orbit?
Well, GRAVITY answers all those questions.
What is gravity? Gravity is an invisible force in our universe that keeps everything together. Gravity is a mystery that has been curious for many great philosophers and scientists. Gravity shapes our world and how we live. The Earth would drifted away from the sun and even the bright moon would have drifted away from the earth. Gravity keeps us from flying off the earth and into space.
Gravity has a lot of jobs.
If you drop an object, it touches down because Earth’s gravity is pulling everybody and everything towards it’s center. If you crumble the paper into a ball and drop the ball and the rock, both fall down eventually at the same time. If the object doesn’t have much mass, the air friction has a more advantage of pushing it upwards, but still gravity pulls it down. That’s what happens when you drop a feather. In a vacuum space, all objects fall at the same rate no matter how much mass it has. Everything which occupies space has a center of gravity and gravity pulls on this point so things can balance.
The pull of gravity makes things go faster as it is falling down. For example, let’s take a rollercoaster. You feel so thrilled as you go down because the gravity changes the speed(acceleration)of the coaster as it goes down a hill.
Some things seem to defy gravity like birds and airplanes. They depend on wings to push air below them and blast up into the sky.
What happens to skydivers when they fall down? Their parachute gets air pushed below them (which is called air resistance). Gravity still pushes them down, but the resistance causes them to land slowly and safely.
In space, however, there is no gravity so the astronauts float like a blob. All the planets, sun and stars have gravity. Objects with more mass have higher gravitational force. But distance affects gravity. As distance increases, gravity decreases. The Sun has a lot of mass but Earth and other planets being so far to it, it is at a distance that the Sun can’t fully pull them in. This keeps planets in their orbits around the sun.
That same concept happens with the moon and Earth. The Moon has less mass than Earth, so it goes around Earth.
Can you imagine reducing weight without diet or any exercise?? Yes, you can. Just climb to the top of the mountain. Ha ha, Not a easy way. Gravity plays a role here too.
The difference between mass and weight is that the mass doesn’t change with the strength of gravity, but weight changes with the gravity. When you’re high up on a tall mountain, your weight reduces a bit because gravity is reduced, but not your mass.
Galileo is a 1600 C.E. scientist that proved that heavy and light objects reach the Earth at the same time. He went to the top of the Leaning Tower Of Pisa. He dropped 1 heavy ball and 1 light ball. Both fell at the same time. He also proved that objects speed up as they fall down. He made something called the Galileo ramp and for time measurements he used falling water. He was always right. A 17 C.E. a physicist named Isaac Newton made a famous gravity equation, “ F = ma”.
He wondered about gravity after an apple fell down while he was resting. He had leftover questions that had to be answered by 19 C.E. scientist Albert Einstein. He did some really good thinking.
· A black hole has immense gravity that not even light can escape, yet it is not that big.
· The height of a person changes over the course of the day because gravity squeezes the fluids in your spine when you are standing for a long time.
· The reason it’s hard to lift heavy objects is because Earth’s gravity pulls more because of the weight. Weightlifters have to be strong enough to fight against gravity.
· It’s important to exercise your back muscles as your front muscles. Then it can overcome gravity’s effect on our body posture.
· The reason tides happen is because of the moon’s gravity which causes the ocean to rise and fall. Moon gravitational force causes tides(change in ocean water level).
Article written by : PIYUSH
Age: 8 years
School: Dingerman Elementary School, San Diego, California
Published on: 29th June 2021