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Gravity, or GRAVITATIONAL FORCES are when one object attracts another. We're not talking about finding someone really cutey-wootie, awwww! We mean when the molecules of one object pull on the molecules of another object. It's like the Earth pulling on you and keeping you on the ground. That's gravity at work. Every object in the universe that has mass, has a gravitational force. Even you do, but when you compare your mass to the mass of the Earth, your gravitational force isn't very impressive. EARTH'S GRAVITY Obviously gravity is very important on Earth. There are other planets that affect our world as well. Our connection with the moon's gravity makes the tides happen. The Earth's gravity even keeps our planet orbiting the Sun, just like the Sun's gravity pulls on us. When the earth spins and gravity pulls on the clouds, weather can be effected. We have to bring up an important idea now. The Earth always has the same pull on every object. If you drop an acorn, or you drop a piano, they will fall at the same speed. It is the Earth's gravity and pull makes objects accelerate when they are falling. It constantly pulls and objects constantly speed up. FEATHERS People always say, "What about feathers? They fall so slowly." Obviously there is air all around us. When a feather falls, it falls slowly because the air is in its way. There is a lot of RESISTANCE and that makes the feather move slower. The forces at work are exactly the same. If you dropped a feather in a container with no air (a vacuum), it would drop as fast as a baseball. |