TOC: GRAVITY2/13/12

Starter

• This weekend I took a trip - I traveled 120miles for 2 hours. What was my average speed?

• This weekend I am going on another trip. This Time I am traveling 180 miles, If I go at the same speed as in question number 1, how long will it take me to get there?

II. PRACTICE: GRAVITY NOTES• Write all notes in Practice Section

GRAVITY

DISCOVERED BY ISAAC NEWTON

•Gravity - The Force of Attraction between two objects

The Force that causes things to fall downExample: if a pencil falls off a desk, it will land on the floor, not the ceiling

SPEED OF GRAVITY

• Gravity pulls objects to Earth at a Speed of 9.8m/s (only changes with air resistance)• Will a baseball and a soccer ball fall at

the same rate? Will they hit the floor at the same time?

• Air resistance - the opposition of the atmosphere to forward movement; also called aerodynamic drag

• Centrifugal force - an outward force on a body rotating about an axis, assumed equal and opposite.

• Isaac Newton studied the earlier Scientists ideas that everything revolved around the sun

• Newton discovered WHY all planets stay around the sun – with many calculations- he discovered that the same reason the apple hit his head was the reason we stay in orbit around the sun!!!!

• This reason was GRAVITY!!!!!!

III. APPLICATION

Draw and Describe each of the Demo’s - Answer each of the questions in at least 2 descriptive sentences each.

Demo 1: Gravity - Text Book & Balled up Piece of Paper

Demo 2: Gravity- Balled Up Piece of Paper & Flat Piece of Paper

Demo3: Centrifugal Force (Gravity in orbit) - Ball on a String

CONNECTION

1. In Demo 1 & 2, did the objects fall at the same rate? Yes or No. If no, explain.

2. In Demo 1 & 2, What forces do you think caused them to fall at different rates (if they did)?

3. In Demo 3, explain how this demo is a model of the sun and the Earth (or any other planet) in orbit.

4. In Demo 3, Explain how the string acts as the force of gravity.

5. In Demo 3, Explain what happened as the force of gravity went away? What direction did the ball (planet) go?

IV. EXIT:

• Summarize in 7 sentences what you learned about gravity. Explain how the demos demonstrated Gravity. Be Descriptive!!!!!