If you missed today:  2013-2014  IMPULSE

Einstein Board:   Impulse - F t  .... increase the time of impact will decrease the force on object (you most likely)

1.  Problem 1 on hmwk sheet  pd 1  pd 2  pd 3  pd 8
2.  Front of desk demo about definition of stability being .... An object is stable as long as the center of mass is over the base.
3.  Problem 2 on hmwk sheet
4.  Back of classroom demo ... throwing egg into sheet
5.  Problem 3 on hmwk sheet
6.  Resource center demo...throwing squishy ball at chalky blackboard

Stability Demo on front desk 8th period

Egg thrown into held up sheet to increase the time of impact so egg can survive the force.

Dropping the Weight on a soda can with egg attached to weight.  Ring stand used also.

Throwing squishy ball at chalky board so very short time of impact ... huge force.  Don't hit the tree or the buck instead hit the brush or the fawn if they are your only choices.

Truthfullness

If you missed today:

1.  Students grabbed any one or two of the five cut-out center of mass figures:  clown, acrobat, parrot, butterfly you color, or butterfly already colored and a scissors and started cutting them out.  Later they picked up a penny or two and taped it to the needed places to move the center of mass to the correct location to hang it from.

2.  I choose a student to go in back of the classroom and actually measure to the center of mass of the funnel demo on the low end and again with the funnel at the high end and proved that the center of mass actually rolled downhill on the demo when the object appears to be rolling up hill.

3.  Had a student volunteer to sit on the other end of a teeter totter from me and had them weigh themselves.  Then as a class we calculated where the center of mass would be so we could set the plank at the center of mass on two sturdy chairs placed back to back (as a fulcum) and balance ourselves while sitting at the ends of the plank.  We measured the length of the plank and figured out the center of mass two different ways.  Then we actually sat on the ends of the plank with the fulcum at the center of mass we just calculated and proved we could balance there.  Now you can finish the problem on the homework sheet to find the center of mass.

4.  Next students brought a piece of paper to the back of the classroom and were showed four bottles of water with a different level of water in each one.  An empty one, one about 1/4 full of colored water, another 1/2 full of water, and a last one full of colored water.  the bottles were lined up against a meter stick taped to a long table and the table was lifted on one end slow but sure as the bottles toppled over.  Students wrote down the order they thought the bottles would fall before the demo and if correct handed the paper in for extra credit.  A student caught the bottles as they toppled.

5.  Next students each got a table fork, spoon, a water glass, and a toothpick and were asked to slide the fork and spoon together and place the toothpick through the middle tine on the fork and balance the system on the outside lip of the water glass.   After balancing they burned both ends of the toothpick to prove that the center of mass is a point.
6.  We next went over the notes on the following two sheets quickly:   center of mass handout, and stability handout