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Elanora High STEM students celebrate calculating constant

Year 11 students, Zavian Riddle and Rafaella Sabroso with their experiment​.

​​​​​Two students from Elanora State High School, recently repeated scientific history by recreating an experiment from the 1770s to calculate the Universal Gravitational Constant, accurate to within one decimal place.

Deputy Principal Shirley Booth said the Year 11 students, Zavian Riddle and Rafaella Sabroso, recreated the Cavendi​sh experiment, originally designed by Henry Cavendish to determine the density of the Earth.

“Cavendish’s experiment used the movement of small objects to measure the gravitational attraction of larger masses which slightly attract the smaller masses,” Ms Booth said.

“Zavian and Rafaella designed a unique interpretation of Cavendish’s experiment using two coconuts attached to a plank of wood which was suspended from a wire in the ceiling.

“They measured the slight movement of the apparatus, which was caused by two coconuts being slightly gravitationally attracted to two 4kg shotputs.

“The students’ calculations to determine the Universal Gravitational Constant were accurate to within 10% of the original calculated value by Henry Cavendish.

“The entire experiment is essentially a test of classical mechanics, namely Newton’s Law of Gravitation. This law, first published in 1686, is a physical law which not only is applicable on Earth, but throughout the universe.

“Although Newton’s law was superseded by Einstein’s Theory of General Relativity for more accurate astrophysical analyses, this classical law provides excellent approximations in localised experiments as modernised by the two students,” she said.

Zavian said calculating an accurate value of the Gravitational Constant was memorable.

“I really enjoyed conducting the experiment; it was fun to see that we could replicate an experiment done hundreds of years ago and get a similar result,” he said.

Creative Commons Attribution 3.0 Australia (CC BY 3.0) ( )
Last updated
17 September 2018