note: if class is small, divide into stations. For largest class, demonstrations. Bring tops.
Forces make stopped objects move and moving objects stop.
Have two volunteers jump. What made them come down? What made them go up (prompt for muscles)? Drop pencil. What made it fall?
Catapult... what made ball fly?
bouncing ball... what happens when it bounces? bounce clay. Now what do you think happens? Push in ball -- what happens to surface? Push in clay? How does ball act like muscles?
"Center of gravity"... what does that sound like? Place where things balance.
Put hat and string on someone's head. have them stand with legs apart. Where is center of gravity? Now stand on one leg. Where is it?
partner control -- have two kids. Ones sits on chair other puts thumb against first one's forehead. try to stand up. What happened with center of gravity?
have child prove they can bend to pick up pencil. Now, stand with toes to wall. Take 3 toe-heel steps back. pick up a pencil (they can't). What happened with center of gravity when you stick your hips way out?
Balance an improbable object with pencils (ball of clay on fork) How did that change center of gravity?
gyroscopes and tops -- precession causes motion in a circle. What makes a good top? How could I turn clay into top?
Gyroscope and bike wheel
coke bottle demo
Hot wheels roller coaster (but only use kids who have earned tokens)
Penny inside a balloon -- spinning things change their behavior. Throw balloon with spinning penny. What happened?
