As of 2014, science remains uncertain about what causes gravity, which is the attraction between two bodies. However, one theory is that small particles called gravitons are responsible for the force. Scientists continue... More »

What causes gravity remains a mystery. Einstein’s general theory of relativity states a massive object curves space-time, causing other bodies to move toward it. This theory helps explain why gravity can act at a distanc... More »

To the extent that scientists understand gravity, it is a product of geometry; gravity is a curvature in the space-time continuum, and the extent of the curvature is determined by the extent of an object's mass. The curv... More » Science Astronomy

The force of gravity is an attraction that pulls all matter together. Matter is inherently attracted to other matter, due to the force of gravity. As more matter binds itself together, it exerts more gravity. More » Science Physics Motion & Mechanics

Projectile motion is caused by gravity's effect on the path of any object that is launched or thrown, according to HowStuffWorks. Projectile motion has both horizontal and vertical components. The horizontal component is... More » Science Physics Motion & Mechanics

A canal lock connects two bodies of water at different elevations by creating a water elevator of sorts. The water inside the lock can be raised and lowered independently, allowing ships to make the transition between el... More »

Friction is the resistance force that appears when two bodies or substances are rubbed together. It slows things down and opposes motion. Without friction, people would not be able to walk, run, write or play sports. Thi... More »