PhSc 206
Sunset Part
1
Name/Section
_______________________________ Name/Section
_______________________________
Name/Section
_______________________________ Name/Section
_______________________________
You should try to do this lab with one or two other students.
Make the following observations. Be careful when
looking
towards the
sun. Never look directly at the sun without appropriate
protection.
(You can use the solar filter available at the bookstore.)
Remember - those are your eyes. (If you feel
uncomfortable
viewing,
there is probably a reason for that!)
Go somewhere to watch the Sun set. Remember exactly where
you're
standing so you can look from that spot again next week (you will
repeat this observation in Part 2 to look for
changes). Before you observe, look up in the newspaper (or
on-line) what time the sun is supposed to set. This way you
will
know when you need to start observing (at least 30 minutes before
sunset). If it looks like the sun will be setting behind a
mountain, you may need to start observing more than 30 minutes before
sunset. Be sure to read all of the questions so you don't
miss
any observations.
Date: ________________________
"Official" sunset time: ________________________
1. Sketch - Start with a piece of graph paper (or print your own http://www.printfreegraphpaper.com). Use your fist as a scale for your sketch - make one
inch on your paper correspond to one fist width.
Very carefully sketch the portion of the horizon where the
Sun sets. Sketch at
least three fist widths to the North and South (right and
left) of
the sunset point. Be sure to include any identifying features
on
your sketch. For example, if you do this from campus, you
might
have Perrin's Peak or Smelter Mountain in the picture. Be sure to label a scale for you plot. (degrees!)
2. Record - As you are
watching, draw the location of the Sun 3 times: once as it
"touches the ground", once 10 minutes before that, and once another 10
minutes before that. Put all "three Suns" on the same sketch to
show the direction of the Sun as it moves toward the horizon.
Do
your best to draw the sun the correct size.
How big is the sun compared to your
fist? _________________________(draw it that way!)
3. Find West - Indicate on
your sketch which direction is "due west." There are several ways
to find west: a) You could use a compass, but remember that
"magnetic north" is a few degrees to the East of "geographic north".
b) Use a GPS. c) Look on Google Maps and find a landmark
that is "due west" of your current location.
How
did you determine due west?
Does the sun set north or south of due west?
_______________________
Estimate (degrees) how far north or south of due west the sun is
setting: _________________________
4. Interpret - Write the
date and precise time (down to the minute) of the sunset on your
sketch. Also be sure to label the times for the "pre-sunset"
locations.
How long (to within 15 seconds) does it take the disk of the sun (as
observed through your filter) to cross the horizon?
__________________________
Depending on the slant of any
mountains on the horizon, do you expect your answer to be shorter or
longer than if the horizon were perfectly level?
_________________________
Estimate the angle that the sun's path makes with the horizon.
______________________ Show (and label!) the angle on your sketch.
Attach your sketch.
Most of your grade will be based on the information included on your sketch.