Using a video camera to measure the radius of the Earth

Carroll, Joshua & Hughes, Stephen W. (2013) Using a video camera to measure the radius of the Earth. Physics Education, 48(6), pp. 731-735.

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A simple but accurate method for measuring the Earth’s radius using a video camera is described. A video camera was used to capture a shadow rising up the wall of a tall building at sunset. A free program called ImageJ was used to measure the time it took the shadow to rise a known distance up the building. The time, distance and length of the sidereal day were used to calculate the radius of the Earth. The radius was measured as 6394.3 +/- 118 km, which is within 1.8% of the accepted average value of 6371 km and well within the experimental error. The experiment is suitable as a high school or university project and should produce a value for Earth’s radius within a few per cent at latitudes towards the equator, where at some times of the year the ecliptic is approximately normal to the horizon.

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ID Code: 68830
Item Type: Journal Article
Refereed: Yes
Keywords: earth, radius , video, eratosthenes
DOI: 10.1088/0031-9120/48/6/731
ISSN: 1361-6552
Subjects: Australian and New Zealand Standard Research Classification > EDUCATION (130000) > CURRICULUM AND PEDAGOGY (130200) > Science Technology and Engineering Curriculum and Pedagogy (130212)
Divisions: Current > Schools > School of Chemistry, Physics & Mechanical Engineering
Current > Institutes > Institute for Future Environments
Current > QUT Faculties and Divisions > Science & Engineering Faculty
Deposited On: 19 Mar 2014 22:08
Last Modified: 21 Mar 2014 00:50

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