Thursday, Feb 7, 2008

Went over Math Skills Worksheet
Went over RA 1
Eratosthenes hired someone to walk the distance from Alexandria to Syene counting steps. Possibly done with knotted rope like British spies in India. A step is about 2.5 ft, a pace is a double step = 5 ft. Mille comes from Roman for 1000 paces = 5000 ft. Meter from French revolution in 1789.

Upcoming lunar eclipse on Feb 20, 6 months after previous lunar eclipse. Talked about eclipse seasons caused by tilt of Moon's orbit around Earth.

Motion - Introduction
Aristotle and four essences Earth, Water, Fire, Air and their natural states
Violet and Natural motion
Fifth essence, quintessence - perfection in heavens, natural motion of planets, Sun, and stars is to move in circles.
Heavier object has more Earth and wants to get to ground (natural state) faster than lighter object. Aristotle was correct, heavier objects do fall faster through medium - demo with soap and ball bearings.
Aside - add fire to earth (lead) to get gold -> alchemy -> chemistry

Galileo
Able to visualize world without friction, air resistance
Thought experiments for falling object (light object tied to heavy) and inertia (ball in bowl)

Vocabulary:
distance: what you pay gas for
displacement: how far from some starting point and in what direction
speed: how fast
instantaneous speed: how fast at some instant in time (speedometer reading)
average speed = total distance traveled/ total time of trip
velocity: how fast and in what direction
instantaneous velocity: velocity at some instant in time
average velocity = change in displacement/time interval

Assigned RA 2.2 due Friday
Assigned WA Chapter 2 part 1 due Sunday 10 pm for discussion on Monday

If it is sunny and warm on Friday, we will do rocket lab.