1. Topic 4

2. How do we determine a frame of reference for time? A)Day – based upon one rotation of the Earth on its axis B)Month – based upon the length of one complete cycle of the Moon’s phases C)Year – based upon one revolution around the Sun.

3. What is local time? Local time is measured by a sundial. The position of the shadow provides the time. Therefore the time is based upon the rotation of the Earth as reflected in the motions of the Sun. All locations on the same line of longitude have the same local time.

4. How does local time change as one travels east? west? Local time changes as you travel east by getting 1 hour later every 15 degrees. Local time changes as you travel west by getting 1 hour earlier every 15 degrees.

5. What is solar time? Solar time is a type of local time based upon the Sun. Solar noon is when the sun is at its highest point in the sky.

6. What is mean solar time? Mean solar time is based upon the averaged length of a day. The length of the day will change because Earth’s speed around the Sun varies.

7. What are time zones? Time zones are 15 degree wide bands that have been established to standardize time for similar regions. There are 24 separate time zones.

8. What happens are you cross over the International date line going east? west? When you cross the international date line going east to west you add one day ex: Sunday  Monday When you cross the international date line going west to east you subtract one day ex: Monday  Sunday