Gravitational Force

 

 

 

Learning Objectives

By the end of this lesson, you will be able to understand the concept of gravity as a force that acts between objects, even when they are not in direct contact. You will learn about the factors that influence gravity, including mass and distance. Additionally, you will learn that Earth's gravity pulls objects downward toward its center.

 

Two children hold the ends of a jump rope outside, while three others jump over the rope.

When you jump rope, gravity is the force that pulls you back to the ground.

© amorn/stock.adobe.com

 

 

Lesson Summary

This lesson introduces you to the idea that gravity is a force that can act between objects even if they aren't touching one another. Through video, images, and text, you will learn that gravity depends on mass and distance and that Earth's gravity pulls objects downward toward the center of Earth.

 

An illustration showing that the force of gravity is greater when objects have greater mass and when objects are closer together.

Mass and distance affect gravitational force.

Encyclopędia Britannica, Inc.

 

Key Concepts

1.  Gravity is a force that can act between objects even if they aren't touching one another.

2.  Earth's gravity pulls objects downward toward the center of Earth.

 

Several children stand on a low wall while they each juggle orange and yellow balls.

Gravity makes it possible for these girls to juggle.

© HOSHANG HASHIMI/AFP via Getty Images

 

Background

Gravity is an invisible force that acts on all objects. The force of Earth's gravity is what holds us, and all the objects around us, on Earth's surface. When a ball is thrown into the air, it falls back to the ground because of Earth's gravity. Earth's very large mass (mass is the measure of the amount of matter in an object) pulls on the small mass of the ball, pulling the ball toward Earth's center. The magnitude (or size) of the force of gravity between two objects, such as Earth and the ball, is affected by mass and distance. The more mass objects have, the greater the force of gravity between them. The shorter the distance between two objects, the greater the force of gravity between them. Keep in mind that there is a difference between mass and weight. Mass is the amount of matter in an object, while weight measures the force of gravity on that object.

Studying gravity exposes you to a scientific law that successfully explains many phenomena in the natural world. The law of gravity explains how objects affect one another, how planets and moons orbit, and how the force of gravity is responsible for weight. This topic also helps you contemplate aspects of the universe beyond Earth: outer space, the Moon, the planets, and the Sun.

 

A cartoon shows three children standing on Earth, with arrows pointing from each of them into the center of the planet.

Earth's strong gravitational force pulls everything toward the center of the planet.

Encyclopędia Britannica, Inc.

 

 

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