Estimate the Circumference of the Earth
using Eratosthenes' Method

Assessment

Students will be using strict formulas to calculate the circumference, therefore their answers should be exactly what is below.  However, if they make any mistakes early on with the trigonometry many of their answers will be affected (with the exception of the "North/south distance").  Therefore the students' answers should be evaluated based on the subsequent calculations made with the computed sun angle.

Student Worksheet Questions Score (points)
A: Estimate the circumference of the Earth using Eratosthenes' calculations
1. Circumference of the earth in kilometers: 46,350 km

 6 4 2 Answer is correct and student writes all calculations Answer is correct and student writes some of the calculations Answer is correct w/o calculations OR answer may be incorrect but simple error made in calculations

____/6
2. The answer should provide a thorough explanation in the students' words and include at least one proposed method to repeat Eratosthenes' experiment today .
 6 4 2 Provides clear & organized explanation using supportive facts. Provides explanation using supportive facts. Provides explanation.
____/6
B: Estimate the circumference of the Earth using Eratosthenes' method
1. Eastlake, OH, USA

Circumference (estimate): 26,640 km
Percentage Deviation: 33.4%

____/6
2. Offenburg, Germany

Circumference (estimate): 31,612.8 km
Percentage Deviation: 21.0%

____/6
3. Balgowan, South Africa

Circumference (estimate): 41,251 km
Percentage Deviation: 3.1%

____/6

Circumference (estimate): 40,694.5 km
Percentage Deviation: 1.7%

____/6
BONUS: The answer should provide a thorough explanation in the students' words. Students should realize that the greater distance between the two cities results in a smaller percentage error because a greater central angle results in fewer 'earth slices' with more room for error in the angle measurement.
 3 2 1 Provides clear & organized explanation using supportive facts. Provides explanation using supportive facts. Provides explanation.
____/3
Total: ____/36

(NOTE: this RWLO is based on the Noon Day Project)