I teach Physics at Wheaton High School
in Wheaton, Maryland. I am a 1996 graduate of Indiana University
of Pennsylvania with a B.S. in Physics Education. I was hired that
summer by Montgomery County Public Schools. I am now entering my
second year at Wheaton. For my home page I have decided to list a few of
my favorite albums. My favorite of all time would be Boston's initial
album Boston. It is interesting that this record is the biggest selling
debut album of all time. Especially since they were rejected by just
about every record label and recorded this album in Tom Scholz's house.
I would have a picture of the cover but Boston's
home page wouldn't give me one. But you can go see it for yourself
by clicking on their name. My favorite band of all time would have
to be The
Rolling Stones. No other band has been in the turning out great
albums for the past 35 years.
For the next part of my page I would like to provide an astronomy activity.
Determining the value of Kepler's Constant.
Background:
Johannes Kepler was
an assistant to Tycho Brahe who studied the
heavens and painstakingly recorded his observation. After Tycho's
death, Kepler took his data and studied it for 22 years. The result
of all this was Keplers three laws of planetary motion. His third
law was, "The ratio of the average radius of a planet's orbit about the
sun, r, cubed and the planet's period, T, (the time for it to travel about
the sun once) squared, is a constant for all the planets. This law
can be expressed as:
r 3
___ = k
T 2
The accepted value for k is 3.375 x 1033
m3/yrs2 when r is in meters and T is in earth
years.
Procedure:
We are going to verify this expression using current
data for each of the planets.
Set up a table on your paper which follows this format.
| Planet Name | r (m) | T (earth years) | k (m3/T2) | % difference from
accepted value |
| Mercury | = | = | = | = |
| Venus | = | = | = | = |
| Earth | 1.5 x 1011 | 1.00 | 3.375 x 1033 | ------------------- |
| etc. | = | = | = | = |
Questions:
1. Based on your findings, would you say there is a planetary
constant? Why or why not?
2. What could be some possible reasons behind this?