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ERIC Number: EJ1037243
Record Type: Journal
Publication Date: 2013-Nov
Pages: 5
Abstractor: As Provided
Reference Count: 11
ISBN: N/A
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.
Institute of Physics Publishing. The Public Ledger Building Suite 929, 150 South Independence Mall West, Philadelphia, PA 19106. Tel: 215-627-0880; Fax: 215-627-0879; e-mail: info@ioppubusa.com; Web site: http://journals.iop.org
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