1. Cornerstone charter academy
Gravity Unit
Cornerstone charter academy

2. Bell-Work Instructions Take out a clean sheet of paper.
Write your heading in the top/right corner.
Answer these questions.
1) In your own words, explain the difference (contrast) between
mass and weight.
2) What is the connection between gravity and weight?

3. Gravity t Unit objectives
Objective: Determine the relationship among the mass of objects, the distance between these objects, and the amount of gravitational attraction.
What is mass?
What is weight?
What is gravity?
How does mass and distance affect gravitational pull?

4. Gravity unit (cont.) Mass…What is it?
Mass is how much matter is in an object.
In other words it is how much "stuff" is in an object
Everything that is made of matter has mass.
So anything that is a solid, liquid, gas, or plasma has mass.
Mass…How is it measured?
We measure mass with a triple-beam balance or an electric
balance (there are various kinds)
We are measuring the amount of matter in the object

5. Unit of measure for mass: Grams
examples: milligrams (mg), grams (g), kilograms (kg)

6. Essential learning questions
Weight…What is it?
Weight is the measure of gravity's pull on an object.
In other words it is how "heavy" something feels
Everything that is made of matter has weight.
So anything that is a solid, liquid, gas, or plasma has weight.

7. Weight…How is it measured?
We measure weight by using a scale (there are various kinds).
So we are actually measuring the force of gravity's pull.
unit of measure for weight: Newton's (not pounds).

8. Mass…How Can I Tell the Difference Between Mass & Weight?
Mass does not change from planet to planet like weight does
Example:
A full/unopened can of coke on Earth has a mass of 390g.
The same unopened can on Mars would have the same mass (390g)
A full/unopened can of coke on Earth weighs 3.61 Newtons.
The same unopened can on Mars would weigh 1.20 Newtons
Why? Mars is smaller (less mass) than Earth & therefore has less gravity

9. Diagram 01
Mass 390g
Weight 3.61 N
Weight 1.20 N

10. Key Concept: Gravity is a pulling force (not a pushing force).
is a “mysterious” force found everywhere in the universe that pulls particles of matter together.
Key Concept: Gravity is a pulling force (not a pushing force).
Law of Universal Gravitation
F.Y.I -Isaac Newton is credited with defining this law
The law states that gravity is everywhere in our universe, and that its attractive force changes based on mass and distance.
Reminder: Mass is the amount of matter in an object
Summary: Every particle of matter is attracted to every other particle of matter.

11. Mass Affects Gravity
Objects with more mass have stronger gravity
Look below: (bowling ball and a baseball) both objects are made of matter, so both objects have gravity.
So both objects are being pulled towards each other.
Yet the ball with more mass (bowling ball) has more gravity.
Therefore its pull is stronger (view animation)

12. Diagram 02

13. Diagram 02
Diagram 03
The example of a bowling ball and a baseball is similar to the gravity effect with a planet and a moon.

14. Imagine these two objects are floating in space.
Diagram 04
Look below: (baseball and a golf ball) both objects are made of matter, so both objects have gravity.
So both objects are being pulled towards each other.
Yet the ball with more mass (baseball) has more gravity.
Therefore its pull is stronger (view animation)
This is similar to the gravity effect with a moon and an asteroid
Imagine these two objects are floating in space.

15. Diagram 05 Note the volume (size) of the Sun contrasted with Jupiter
Because it has more mass, it likewise has more gravity

16. Diagram 06

17. Distance affects gravity
Diagram 07
Stronger Gravity
Diagram 08
Affect of gravity increases when objects are closer together.
Affect of gravity decreases when objects are farther apart.
In diagram 07 the two soccer balls are 5m apart (floating in space).
In diagram 08 the two soccer balls are 10m apart (floating in space.
Weaker Gravity

18. Diagram 09 Distance Affects Gravity
The Sun has more gravity than the moon (because it has more mass)
Yet the Moon is closer to the Earth than the sun.
So, the Moon’s gravitation pull on Earth’s oceans (tides) is greater than the Sun’s gravitational pull.

19. Gravity and the theory of relativity
Einstein theorized that mass warps (bends/curves) space and this warping explains the force we call gravity.

20. Practice Questions A) Conservation of Mass C) Universal Gravitation
(1) What is the name of the law about gravity? The law of…
A) Conservation of Mass C) Universal Gravitation
B) Universal Attraction D)Conservation of Gravity
(2) All matter in the universe attracts other matter by?
A) “pushing force” B) A “pulling force”
C) “push and pull force”
(3) The strength of gravity depends on the ______ of the objects
A) Masses B) Shape C) Size D) rotation
(4) Effect of gravity depends on the _____ between the objects.
A) Energy B) Distance C) orbit D) objects
(5) What did Einstein say about mass and gravity?
A) That mass warps space B) Mass and gravity are the same