4 Physical Science Gravity

WHAT IS GRAVITY? Have you ever wondered why things fall? It's because of me! GRAVITY! Nothing in the universe can escape my grasp!

重力是什么？你有没有想过为什么东西会掉下来？ 都是因为我！重力!宇宙间没有任何东西能逃过我的手！

All objects attract one another. This force is called gravity. A force is something that pushes or pulls an object. Gravity is the force that keeps your feet on the ground. If there were no such thing as gravity... ...you would fly up into the air and off into space. How can I be so powerful?!

所有的物体都相互吸引。 这种力叫做重力。 力是推或拉物体的东西。 重力是使你的脚站在地面上的力。 如果没有重力这种东西…… …你会飞到空中，然后飞到太空。 我怎么会这么强大！

The strength of gravity depends on two things: distance and mass. Distance is the space between two objects. The farther apart two objects are from each other, the weaker the pull of gravity between them. Mass measures how much matter an object holds. Everything is made of matter. The more mass an object has, the more it pulls on objects around it. Gravity!

重力的强度取决于两个因素：距离和质量。 距离是两个物体之间的空间。 两个物体之间的距离越远，它们之间的引力就越弱。 质量测量的是物体所含物质的多少。 一切都是由物质构成的。 一个物体的质量越大，它对周围物体的拉力就越大。 重力!

All objects have gravity- even you! Your body's gravity pulls Earth toward you. But Earth has trillions and trillions times more mass than you do. Earth's gravity pulls you toward the ground. That's why you can only jump so high!

所有的物体都有引力——包括你！你身体的引力把地球拉向你。 但地球的质量是你的数万亿倍。 地球的引力把你拉向地面。 这就是为什么你只能跳这么高！

MEASURING GRAVITY Gravity is an invisible force, but we can still measure it. Weight is a measure of the pull of gravity on an object. You've probably weighed things to find out how heavy they are. When we weigh things to find out their mass, we use pounds or kilograms as units of measurement.

重力是一种看不见的力，但我们仍然可以测量它。 重量是对物体的引力的度量。 你可能称过东西的重量，想知道它们有多重。 当我们称物体的重量来计算它们的质量时，我们用磅或公斤作为测量单位。