Gravity

By Asha Duhan

March 6,2011

What is Gravity?

Gravity is a Force Field surrounding the Earth. The Force Field pulls anything that comes in orbit of the Earth towards the Earth. Sometimes an Asteroid gets pulled into the Force Field and makes huge craters in the Earths crust. Other times the Asteroid is seen when it is really tiny (because it burned up) with fire surrounding it which we call it a shooting star; it should really be called a falling star.

Why is Gravity Important?

• If Earth did not have gravity, what do you think would happen? Everything would be floating around including you; perhaps we would not even have an atmosphere. In space there is no gravity or atmosphere.

Who Found out what Gravity was?

• Isaac Newton discovered gravity between 1684 and 1687. Newton was sitting under an apple tree and an apple fell on his head. All of a sudden he started wondering, “What made the apple come down on my head instead of going up?” Newton named it ‘gravity’, after the Latin word gravitas, which means weight.

What Causes Gravity?

• The cause of gravity is one of the biggest mysteries of science. Physicists have studied gravity for a while, but they still don’t know what causes it.

Our Sun’s Gravity

• The Sun’s Force Field is a lot bigger than Earth’s Force Field because the Sun is a lot bigger than the Earth.

• The Sun’s Force Field keeps our solar systems planets in orbit.

Why does Gravity affect your weight on other planets?

• Gravity affects your weight on other planets because gravity’s strength can be stronger or weaker on other planets. For example, Mars has a weaker gravity than Earth, and your weight on Mars is about 1/3 that on Earth. But on Jupiter your weight is 2.64 times as much as your weight on Earth.

Newton’s Laws of Gravity• Newton spent many years discovering the law of gravity. • According to this law everything pulls everything else to

itself with a force called gravity. How strong that force is depends on how heavy the things are and how close together.

• So even two apples pull toward each other. But, the force is so small that you need a very careful experiment to measure it. The reason that things fall toward the ground is that the Earth we live on is so very heavy, and we are so close to it.

• Newton's law of gravity not only explained how things fall on earth, but why planets move around the sun and why moons move around planets.

• http://www.dctech.com/eureka/short-stories/newton.php

How do Rockets get out of Gravity’s pull and into Space?

• For a rocket to go into space, it has to point upwards. Its engine needs to have enough power to beat the pull of gravity, which means the engine must be very powerful to launch the rocket.

Astronauts in the Shuttle in zero Gravity Space

Resources• http://www.qrg.northwestern.edu/projects/v

ss/docs/space-environment/1-what-is-gravity.html

• http://wiki.answers.com/Q/When_did_newton_discover_the_law_gravity

• http://en.wikipedia.org/wiki/File:Solar_sys.jpg

• http://wiki.answers.com/Q/How_does_a_rocket_go_into_space

Resources (continued)• http://www.seismologik.com/journal/2010/7/29/s

pace-stuff-nasa-layoffsthe-asteroid-that-could-destroy-eart.html

• http://blogs.sundaymercury.net/weirdscience/2010/05/newtons-tree-in-space.html

• http://wiki.answers.com/Q/How_does_gravity_affect_weight_on_different_planets

• http://wiki.answers.com/Q/How_heavy_will_you_be_on_Jupiter

• http://matchstic.com/blog/2008/08/months-in-the-making-new-matchstic-site-launch/

The End