Warm Up: Page 30 6 Steps that led Newton to being considered the “MAN” Step1—Understand Galileo’s concept of Inertia. Any change in speed or direction requires a force. Step 2—Sit under apple tree and see the apple falling; see moon through trees. Step 3—Realize that the moon must be falling towards the earth, just like the apple! Step 4—Wonder why moon circles Earth. Step 5—Conclude that a centripetal force must be pulling the moon into circular motion. Step 6—Figure out that the moon falls for the same reason that the apple falls—both are pulled by EARTH’S GRAVITY.

Announcements Newton’s Law Warm-Ups and Work Page 28 Scavenger Hunt Page 29 Universal Gravitation Notes Page 30 Notebook Check tomorrow Open Notebook Assessment Homework Due tomorrow Fruit Sale

Free Fall Place thumb over hole and fill cup What will happen if you remove your thumb? Write down predication Results? Place thumb back on the hole If you dropped the whole cup, would the water fall through the whole? Stand on top of a chair Prediction?

Weight and Gravity Quick write 2 minutes, Page 30: Why didn’t any of the water fall out?

Newton and Gravity Newton thinks, hmm why isn’t any water falling out of the cup? There must be no net force between the cup and the water, that’s why the water stays inside? However there is a force because it falls out if the cup is kept still.

Tennis Ball and a Sheet of Paper Which will hit the ground first? Why?

Brain Pop! http://www.brainpop.com/science/motionsfo rcesandtime/gravity/

2nd Law and Gravity Which law tells us about force? Newton’s 2nd Law: F=ma If water is falling out of the cup, then there must be a force If there is a force, there must be acceleration But wait, how can there be a force if the cup is not moving? That acceleration just from being there! Gravity!

About Weight Weight is a measurement of how hard gravity is pulling on that object. Your weight depends on how much gravity is acting on you at the moment You'd weigh less on the moon than on Earth, and in interstellar space you'd weigh almost nothing at all.

This is NOT a new formula… Gravitational Force = Weight So if then where g = 9.8m/s2 and m = mass F = ma Weight = mg

GP: Making Weight (10) Background: have you ever jumped up and down on a scale, what happens to your weight Objective: See how changing acceleration can add or take weight away Materials: (1) spring scale/group (2) Weight, anything you can find

IP: Fly Me to the Moon (15)

UNIVERSAL GRAVITATION Newton’s Genius

How Universal Gravitation relates to Newton’s First Law… The moon will remain in motion in a straight line if it were not acted upon by an outside force (the Earth’s gravity pulling on it).

Newton’s Hypothesis… He hypothesized that the moon was simply a projectile circling the Earth under the attraction of gravity.

Newton’s Law of Universal Gravitation Newton did not discover gravity. Newton discovered that gravity is universal. Question: How can we increase the force of gravity between two objects?

Center of Mass Demonstrations Move three foot lengths away from the wall. Keeping your legs straight bend down until your head touches the wall. Grab a chair and try to stand up Males versus females http://www.youtube.com/watch?v=sHHWh3 meeJU&feature=related

Challenge: Can you catch a $1 bill Can you catch a $1 bill before it hits the floor using only your index finger and middle finger? Rules Arm out perpendicular, and hand straight out Place thumb, index and middle fingers 1” apart You must only move those three fingers If you catch it, you keep it!

Why Can’t you Catch it? Place reasons on board

Key Take Aways What is the acceleration due to gravity on Earth? Why doesn’t the water fall out of the cup when dropped? Why do all objects on Earth fall at the same acceleration?