E is for Energy, R is for Robot

HMWK (Due Next Tuesday)  Read p. 128-133, p. 133#1-7

Announcement: Robotics Club will meet Thursdays; 2:30 - 4:30.  If you can make that time (or part of that time) work, please get an application and $12 to Mr. Freeman by Monday.  1st "hands-on" meeting is the Thursday after Thanksgiving. 

Today in class:  Conservation of Energy: repeated some of Galileo's experiments, one with ramps and balls, and the other with a giant pendulum. 
Basic ideas:
If you release a ball from one side of an unevenly curved ramp surface (think a skateboarding halfpipe that's uneven), the distance the ball rolls up the other side is not necessarily equal to the distance rolled down.... what DOES matter is the height.  The ball will roll up to approximately the same height as it was released from.  The same holds true with a pendulum; it will return to approximately its release height.  Galileo used this to coin the idea of the Law of Conservation of Energy (from this point on, we'll refer to Energy as just E )
Two parts exist to the Law of Conservation of E.   1. E can't be created or destroyed.  2. E transferrs between different forms and objects. 

A good time to review scientific laws vs. theories;
A law states what happens.  (ex. Energy doesn't appear or disappear - it has never been shown to happen)  (gravity: objects fall down, or objects are attracted to one another, proportional to their mass and distance between them) 

A theory explains why/how something happens.  Theories of gravity exist as maybe involving a particle, or maybe being actually connected to electricity and magnetism in some way that hasn't been discovered yet.  Mass is theorized to be actually the same thing as energy.  Maybe we're all just made of bits of oscillating energy.  (etc.)

Finally, two big types of energy: GPE (Gravitational Potential Energy) = energy stored by an object's position in a gravitational field
KE (Kinetic Energy) = energy in a moving object.