Procedu

This is a lab I have been working on. Can you look over. I am stuck on the end part of the lab. Hope you can help, Thank you.

1. Mark the popsicle sticks a give length down from the top edge. Note that length here __5___ cm

1. Place a small piece of clay at the North Pole of the hemispherical globe. Stick a popsicle stick straight down into the clay, at 90 degrees to the surface.

1. `` Measure a fixed arc length down the longitude of the globe and place a second piece of clay and another popsicle stick. Be sure that both popsicle sticks are sticking out of the surface like flag poles to the ground. It is essential to have radial projection in order to get proper Shadow lengths.

1. Shine the flashlight directly down on the North Pole of the globe. Make sure that the popsicle sticks cast no shadow. This ensures that the ray of light is 90 to that surface.
2. While the light is shining down on the North Pole of the globe, you will notice that the other popsicle stick casts a shadow on the globe.

1. Measure the arc length between the two sticks and record it below

• Measured length between sticks = ___7___ cm

1. Measure The Arc length of that shadow and record it in the space below:

• Measured Shadow Length = ____6_____ cm

1. Calculate the tangent according to the ratio shown. Use calculator and the ration of shadow length to the stick length and list that below:

• Ratio = ____3______
• Calculated angle of insolation = _52___ degrees.

Using the formula calculate the circumference of the globe. 48.5

• 6. Repeat this process on another two locations on the globe. The key to success is to make sure that wherever the first stick is placed, the second stick is on the same longitude, and the flashlight shines on the first stick and casts no shadow.

Location 2

• Distance between sticks = ___1.5_____ cm
• Shadow length of second stick = ___2_______ cm , Ratio = __.46_________
• arctan (ratio) = Calculated angle of insolation = __24.7____ degrees.
• ____30________ cm

Location 3

• Distance between sticks = ______6__ cm
• Shadow length of second stick = ___5_______ cm , Ratio = _______3____ arctan (ratio) = Calculated angle of insolation = ___76___ degrees. Check for accuracy

Now that you have accomplished three independent measurements on the hemispherical globe and have compared each of your results, check for accuracy by wrapping a string along a longitudinal line to measure the circumference of the globe directly. 45 " = 115. cm

The simplest way to do this is to pull the string in your fingers and stretch it across the globe and wrap it around holding each end of the string with the fingers. Next, carefully lift the string and place it stretched out on a meter stick and record the length below.

Direct Measurement of circumference = _________________ cm ?

Finally, calculate the percentage of error between the direct measurement, which should be treated as the accepted value, and the average the three trials as the experimental value.

Location 1

Location 2

Location 3