1. Gravity: The Force of Attraction
Unit 7
Section 4

2. What is Gravity?
Gravity is a force of attraction between objects that is due to their masses.
Mass is the amount of matter (or stuff) in an object.
(Mass Always Stays Same)
This means that all objects experience gravity between them.
The bigger the objects are, the more gravity that exists between them.
1. For example-A planet has more gravity than a person.

3. Gravity
e. On Earth, all objects fall toward the center of Earth’s mass. f. Gravity can change the motion of an object by changing its speed, direction, or both

4. Newton and Gravity
Sir Isaac Newton was a scientist who first recognized gravity when an apple fell from a tree.
Newton realized that gravity depends on the mass of objects AND the distance between them.
This was called the Law of Universal Gravitation

5. Law of Universal Gravitation
Gravitational force increases as mass increases.
The sun has a stronger gravitational force than our moon because it has a greater mass.
Gravitational force decreases as distance increases.
When we leave earth in a space ship, we are getting further from Earth’s gravitational pull so we will float around in space.
(distance increased so gravitational pull will decrease)

6. Weight
Weight is a measure of the gravitational force on an object. Weight how much gravity is pulling down on an object.
Weight can change, depending on where you are in the universe and how much gravity there is.
The bigger the planet, the greater the gravity there is and you will weigh more.

7. Weight
How much do you weigh...

8. Quickie Quiz What is the amount of stuff in an object? Weight Mints
Mass
Fluff

9. Quickie Quiz As mass increases gravitational force will Decrease
Stay the same

10. Quickie Quiz On the moon, your mass will Decrease Increase
Stay the same

11. Answer These Questions
Explain the law of universal gravitation
Describe the difference between mass and weight

12. Answers
Gravity is a force of attraction between objects that is due to their masses. All objects experience gravity between them.
Gravitational force increases as mass increases. Gravitational force decreases as distance increases.
Weight can change depending on where you are in the universe and how much gravity there is, but mass always stays the same.