Investigation 3, Part 3 Timekeeping
Warm up: • What direction does the Earth rotate on it’s axis? • When the sun shines on a sphere, how much of it can be illuminated? • Counterclockwise • Exactly half
Timekeeping • Is it the same time everywhere in the world at the same time? • No • If there are different times in different places on the globe, how do we figure out exactly what time it is? • We might use the sun. • When does a new day start? • Midnight, 12 am, or 0:00 (military time) • Noon is half way through a day. 12 pm or 12:00 (military)
Timekeeping • Noon is when the sun stops rising and starts to set. This is known as local noon. • Local noon is 12 pm, no matter where you are. • When is local noon here? • Sun is highest in sky. • Sun stops rising and starts setting. • Exactly halfway between sunrise and sunset. • Calculate local noon. • http://weather.yahoo.com/united-states/arizona/phoenix-2471390/
Assignments • We will use the Local Noon ws 17 to help us calculate our local noon. • Finish How Many Hours Have You Worked, ws 15.