You are all probably aware that the sun rises in the east and sets in the west due to the earth's rotation. What you may not have noticed is that the exact location at which it rises and sets, and the path that the sun follows through the sky changes throughout the year. In this section of the lab, you will observationally investigate the nature of these changes.
Observations
The observations for this portion of the lab will require you to do multiple observations of the sunset throughout the course of the quarter.
1. Find a place from which you can observe the sunset and make a note of the precise location (choose a bench or a tree since you will need to return to this EXACT location to do all of your observations). You will be making multiple observations throughout the quarter so make certain that it is an easily accessible spot.
2. For your first observation, you need to arrive before sunset
in order to make a sketch of the western horizon. Make certain
that your sketch includes some landmarks that will act as reference
points against which you can compare the changing location of
the sunset.
3. Observe the location of the sunset relative to your reference
points and include it in your sketch making a note of the date,
time, and location of your observation.
4. Repeat this observation approximately once a week throughout
the course of the quarter and draw the location of each subsequent
sunset into your ORIGINAL sketch.
5. In addition to your sketches, make a table to record your observations,
and include the following information for EACH observation:
* The date and time of the observation
* The number of days since the previous observation
* The direction that the sun has moved since the previous observation
(north/south)
* The number of degrees that the sunset has moved since the previous
observation
* The approximate rate at which the sunset has moved during the
period since the previous observation (To compute this rate, simply
divide the number of degrees that the sunset has moved by the
number of days since the last observation.)
Answer the following questions
1. What is causing this change in location
of the sunset?
2. Did the sunset move in the same direction between each of your
observations?
3. Would you expect the sunset to move in the same direction all
year? Why or why not?
4. Was the rate of movement the same between each of your observations?
What is the rate of movement of the sunset over the course of
the quarter (between your first and last observation)?
5. Would you expect the rate of change to be the same all year?
Why or why not?
6. How do you expect the location of sunrise to have changed during
this same time interval? What does this mean about the path that
the sun is taking across the sky?