Finding the Radius of the earth.
Basic Idea:
We'll use the north star (polaris) to give
us information about the radius of the earth. Later, we'll
use measurements recorded by various people, along with some
statistical tools, to estimate the radius of the earth.
Since the north star sits over the north pole, and is very
far from the earth, it appears to be high in the sky if you
are near the north pole, and low in the sky if you are near
the equator. If you're in the southern hemisphere, you won't
be able to see it. So how high up the north star is tells you
how far north you are.
Don't worry about these details, for now all you need to do is
measure how high in the sky is the north star.
Finding the north star:
The best way to find the north star is to wait until
night time and find some one who knows where it is to
show you. Failing that, you find the big dipper and
use the two stars opposite the handle as a pointer to
the north star. Good luck.
Finding the angle:
Here's one way to find the angle of the vertex created
by the north star, you, and the ground. Take a simple
semicircular protractor which has a hole at the circle
center. Tie a piece of thread thru the hole and tie a
small washer to the other end of the thread. Place a
straw on the straight edge of the protractor and site
the north star thru the straw. Have someone mark where
the thread crosses the curved edge of the protractor.
The angle given by the washer, the hole, and the north star
is the angle we want. You should be able to read that off
from where the string crosses the protractor.
Determine your lattitude and longitude.
This can be done by looking up the coordiantes for your
particular location. If you have a GPS device, it will give
you your lattitude and longitude.
When you get back, email me your lattitude, longitude, and angle.
Any sincere effort will allow you to replace your lowest quiz
score with a 10.