Day and Night

Title: Day and Night (Observing a phenomenon) Problem: What causes day and night? Why do we have different time zones?

Hypothesis: 1.

Part A - Procedures: For this model a lamp will represent the "SUN" and your body will represent the "EARTH". Your eye/nose will be an observer that is on earth.

1. If your body represents the earth what hand would be the east coast and which would be the west coast? Explain how you know. East:

2. Move yourself or the sun to show how your observer (your eye) can experience day and night. Explain what you did.

3. How would you position your "Earth" so that your observer (eye) is experiencing noon and then midnight? Explain what you did.

Noon (12 pm):

Midnight (12 am):

4. How would you position your "Earth" so your observer is experiencing sunrise (the sun coming up on the east side)? Then sunset (the sun going down on the west).

Sunrise (6 am):

Sunset (6 pm):

5. Figure out which direction the Earth moves. Describe what you did.

Part A – Reflection Questions:

1. Why is it dark at night?

2. At any given time, how much of the Earth is in day and how much is in night?

3. On average (with no tilt of the earth) how many hours is day and how many hours is night?

4. What is the cause of day and night?

Part B – Procedures: When a body turns or spins in a circle like a top, we refer to that motion as rotation. The imaginary point on which it turns is called an axis. Show night and day again, this time using a small globe to represent the earth; the sun is NOW represented by you. On the globe find the United States – in the Northwest corner is Seattle, in Washington State. 1. Demonstrate with the globe how the earth experiences night and day. Describe what you would do to the globe, draw or explain the each of the following. a. Orient the globe so the observer (Seattle) is experiencing noon.

b. Orient the globe so the observer (Seattle) is experiencing midnight.

c. Orient the globe so the observer (Seattle) is experiencing sunrise.

d. Orient the globe so the observer (Seattle) is experiencing sunset. Part C – Procedures: Because different parts of the earth are exposed to sunlight at different times during its rotation, the planet is divided into 24 time zones, roughly by lines of longitude. The starting point for the time zones is the prime meridian or the line of longitude that passes through the Greenwich observatory in Greenwich England. There are 12 time zones to the west of the prime meridian and 12 to the east. The time zone to the east is one hour LATER, and the time zone to the west is one hour EARLIER. The dotted line opposite of the prime meridian (A) is the International Date Line, where a new day begins. (Past this line is a different day)

Follow the pattern and Label the time zones:

Reflection Questions: 1. If it is 6:00 p.m. in Greenwich England, What time is it in: Alaska (main) ______Washington DC ______Seattle ______Japan ______Great Britain ______2. If it is Friday at 6:00 p.m. in Greenwich, what day and time is it in Japan?

3. What does the dotted line represent? Why is this important? (think about it)

4. What makes the sun "come up" and "go down?" If the Earth did not rotate, would there be day and night on Earth?