This is an archived page from the Website Archive of British artist Ellie Harrison from Version 3.0 (active 2008 - 2015). New website: www.ellieharrison.com The Potential Generator is a kinetic sculpture designed to give gravitational potential energy to apples. Apples are placed on the escalator device at the rear of the bike and, as a result of the bike being pedalled, are transported to height above the ground proportional to their chemical energy content. A similar, but proportionally larger, Potential Generator for doughnuts was also designed. This can be viewed by clicking on the link to the right under ‘Further Reference’.

Gravitation potential energy (E) is possessed by any object, of mass (m), held at a height (h) above the Earth’s surface. This energy is the result of the immense force of gravity (g) produced by the Earth’s mass. The Earth’s gravity produces the acceleration of an object towards it at a rate of 9.81 metres per second. The gravitation potential energy possessed by this object is found by the equation: gravitation potential energy = mass × gravity × height.

In order to calculate the proportionate heights for the Potential Generator for apples and the Potential Generator for doughnuts a series of calculations were performed:

An apple (Granny Smith) of mass 0.2kg has a chemical energy content of 408,000 Joules and a jam doughnut of mass 0.1kg has a chemical energy content of 1,129,000 Joules. By hypothetically equating these energy values to gravitation potential energy, it is possible to calculate the height above the Earth’s surface an apple and a doughnut would exist at if there could be a direct conversion between energy types.

By rearranging the equation above (h = E / mg) you find that if an apple’s chemical energy content was in fact gravitational potential energy, it would exist at a height of 207,951 metres above the Earth’s surface, and a doughnut would exist at 1,150,866 metres above the Earth’s surface.

The Potential Generator machines are scaled to one millionth of these values. The escalator device on the back of the Potential Generator for apples provides a height of 0.21 metres and the escalator device on the back of the Potential Generator for doughnuts provides a height of 1.15 metres.