From: ckeer_at_lourdes.k12.pa.us
Date: Thu Sep 30 2004 - 08:57:04 PDT
Experiment Report for the Eratosthenes Project on http://youth.net/ School Name: Our Lady of Lourdes Regional High School School Location: Coal Township, PA, USA Email Address: ckeer_at_lourdes.k12.pa.us Experimenter: Mr. Keer's Trigonometry Class Latitude 40.7862N Longitude: 76.5840W Distance to Equator: 2821 Measured shadow angle in degrees: 43.1478 Calculated Earth circumference: 23536.8 mi, 37901.45 km Comments: Since our class meets from 10:30-11:15AM, we could not meet at local noon. We knew that the shadow traces very close to an East/West line on the equinox and used this to predict the length of the shadow at local noon. We did this by marking the position of the tip of the shadow at regualar intervals of time. We connected the points to form the East/West line. The position of the shadow at local noon was found by drawing a line perpendicular to the EW line through the point where the stick was positioned. Since we are a trig class, we used the inverse tangent function to find the latitude based on the ratio of the lengths of the stick and shadow.