# Review Energy-8

1. ### Wind turning a windmill.

No. The moving air is pushing against the blades of the windmill. Because a physical object (moving air) is pushing on the windmill, this is a contact force.
2. ### Sound causing you to hear something.

No. For you to hear a sound, the vibrations of the object make the air vibrate. That is a contact force because there is direct contact between the vibrating object and the air. The vibrating air is in contact with your ear drum, causing it to vibrate too. That lets you hear the sound. Because a physical object (vibrating air) is moving your ear drum, this is a contact force.
3. ### Gravity causing a rock to fall.

Yes. The gravitational attraction between the Earth and the rock does not need physical contact. The rock would fall, even if it was in a total vacuum, with no physical object to push or pull on it. This is a force acting at a distance.
4. ### Throwing a ball to knock over a target

No. To throw the ball, your arm pushes against it. Your arm moving the ball is a contact force. The moving ball hits the target to knock it over. The ball is touching the target to knock it over, so this is also a contact force.

### Florida

SC.5.P.10.3 Investigate and explain that an electrically-charged object can attract an uncharged object and can either attract or repel another charged object without any contact between the objects.

#### >>> Teacher Page: Electrostatic Charges

 Challenge: Paper, Coin, Cup, part 1 video Electrostatic Charges video The Leyden Jar video Versorium video Electrostatics and Water video, ClosedCaptions Challenge: Paper, Coin, Cup, part 2 video Sorting Salt and Pepper video Electricity video, free, Updated Making Water Wiggle video Review Energy-6 quest Review Energy-7 quest Review Energy-8 quest

SC.6.P.13.1 Investigate and describe types of forces including contact forces and forces acting at a distance, such as electrical, magnetic, and gravitational.
 Challenge: Paper, Coin, Cup, part 1 video Making a Compass video Torque video Versorium video Water in a Glass, part 2 video Water in a Glass, part 3 video Water in a Glass, part 1 video Challenge: Paper, Coin, Cup, part 2 video Light a Bulb with a Balloon video Crushed Can video Electricity video, free, Updated The Compass and Magnetic Fields video, ClosedCaptions Review Energy-6 quest Review Energy-7 quest Review Energy-8 quest

### Utah

UT.3.IV.2.c Pose questions about gravity and forces.
 Water in a Glass, part 2 video Water in a Glass, part 3 video Water in a Glass, part 1 video Planets and Pennies video, ClosedCaptions Force, Pressure, and Shoes: Updated video Balancing a Meter Stick text page Review Energy-8 quest Review Space-13 quest

### NGSS

MS-PS3-2 Develop a model to describe that when the arrangement of objects interacting at a distance changes, different amounts of potential energy are stored in the system.
 Measuring Kinetic and Potential Energy video Challenge: Paper, Coin, Cup, part 1 video The Leyden Jar video Versorium video Water in a Glass, part 2 video Water in a Glass, part 3 video Water in a Glass, part 1 video Electrostatics and Water video, ClosedCaptions Challenge: Paper, Coin, Cup, part 2 video Sorting Salt and Pepper video Making Water Wiggle video Review Energy-6 quest Review Energy-7 quest Review Energy-8 quest