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ERIC Number: EJ1037243
Record Type: Journal
Publication Date: 2013-Nov
Pages: 5
Abstractor: As Provided
Reference Count: 11
ISSN: ISSN-0031-9120
Using a Video Camera to Measure the Radius of the Earth
Carroll, Joshua; Hughes, Stephen
Physics Education, v48 n6 p731-735 Nov 2013
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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Publication Type: Journal Articles; Reports - Research
Education Level: Secondary Education; High Schools; Higher Education; Postsecondary Education
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A