Aristotle used observations of a lunar eclipse to determine that the Earth is spherical in shape, more than 1,500 years before Columbus!  You are going to walk in his footsteps in this lab.  This lab requires you to come prepared with some answers to questions before the lab.  Come to class on February 20th, 2008 with the following:

1.  A sketch that shows the Sun-Earth-Moon positions in space during a lunar eclipse.  Label both the umbra and penumbra.  (You can find this in your astronomy text).  

2.  A sketch of what you think the Earth and Sun would look like from the Moon just before the eclipse begins.

3.  Definitions for the following terms - penumbra, umbra, lunar limb, total lunar eclipse, partial lunar eclipse, and penumbral lunar eclipse.

4.  An explanation that includes a sketch of why the Moon often turns red during a total lunar eclipse (you can find this in your astronomy text or on-line).

5.  Cut out circles of the following diameters from construction paper - 1-inch,  2-inches, 2.5-inches, 3-inches, 3.5-inches and 4-inches.

6.  Bring to class the following materials - a new pencil or a long pen.  Tape. A tape measure. 

Directions.

1.  Observe the lunar eclipse using your eyes, binoculars, and a telescope.  Make a sketch every 30 minutes to show the progress of the eclipse including the description of the color of the Moon.

2.  When the Moon is about half-way into the umbra,  determine the relative size of the Earth's shadow and the Moon using the materials that you made and brought to class as shown by your instructor.

3.  Note - you will find yourself with some extra time so you should start working on the Constellation Lab..

Questions.

1.  Explain how Aristotle determined the shape of the Earth from observations of a total lunar eclipse.

2.  What was the size of the Earth's umbra compared to the size of the Moon?   Is the size of the Earth larger than it's umbra or smaller than it (refer to your sketch that you prepared prior to class)?

3.  Who first measured the diameter of Earth?  When was this done?  The diameter of the Earth is 12,700 km.  Use this information to estimate the diameter of the Moon from your observations of the lunar eclipse.

4.  From your sketches, estimate how long it took for the Moon to traverse its own diameter.  Using your answer from the previous question, determine how fast the Moon is traveling in its orbit around the Earth measured in km/hr.