Thermometer Statue

A public statue that tells the temperature using only the way different metals expand.

A design project for my M.Eng. coursework (2012). Wrought aluminum expands about twenty times as much as Invar with each degree of temperature change. The green beams are aluminum and the rest of the structure is Invar (a nickel–iron alloy), so as the temperature changes the beams move relative to the frame. To produce a readable scale of one centimetre per degree Celsius you would need a straight beam 413 metres long. Instead, one-metre beams drive stages of levers that multiply the movement 400 times, like the lenses in a microscope, to turn the needle on the dial. It is symmetrical on both axes, so the weights of the beams cancel out and the levers are balanced to negate any loads that might affect the reading.

The design takes its look from large Victorian clocks and uses the golden ratio in its proportions.

Both pictures are SolidWorks models, colourized and made partly transparent to show the mechanism.

Pictures