Year 11 Physics: The Eratosthenes Project

Year 11 Physics: The Eratosthenes Project

Olivos & Nordelta – December 2020

 Our Year 11 Physics students participated in the Eratosthenes 2020 project, organised by the Department of Physics of the Facultad de Ciencias Exactas y Naturales de las Universidad de Buenos Aires; the Pierre Auger laboratory of the Universidad Tecnológica Nacional, Facultad Regional Mendoza and the Asociación Física Argentina.

53 schools have participated in this project: 21 from Argentina, 11 from Brazil, 10 from Spain, 1 from Portugal, 1 from Greece, 2 from Venezuela, 1 from Uruguay, 5 from Romania and 1 from the United States.

The measurements were obtained between September 11th, 2020 and October 9th, 2020 at solar noon. With the results reported by the
schools, the optimisation of the North-South component of the distance was considered. Pairs of schools were chosen by maximising the North-South component of the distance and considering that they carried out the measurements on the same day. In this way 166
pairs of schools were selected.

The radii obtained from the measurements reported by the schools were calculated and 63 data were discarded because they were more than ¼ of the expected terrestrial radius value.

The mean value obtained was R = 6 176 km and the standard deviation, which gives an idea of ​​the variation of the set of values obtained, was 386 km. The standard error of the mean, which is obtained by dividing the standard deviation by the square root of the
number of measurements, resulted in 30 km. Therefore, the Radius of the Earth calculated was R = (6 170  30) km. The error is only statistical, since estimates of the errors in the measurements have not been considered.

According to the accepted values, the mean terrestrial radius is R = 6 370 km, a value that is around 3% higher than the result obtained.
The result obtained considering only the measurements of Y11 students was R = 6 560 km. In this case, the accepted value is around 3% less than the result obtained.

Congratulations to all students who participated: Trinidad A., Manuel B. A., Pedro de A., Donatella F., Mateo F., María Delfina H., Mateo L. T. B., Lukas M. B., Elida P., Tomás W. y Bárbara W.