Portal:Scotland/Selected article/Week 4, 2008

The Falkirk Wheel, named after the nearby town of Falkirk in central Scotland, is a rotating boat lift connecting the Forth and Clyde Canal with the Union Canal. The difference in the levels of the two canals at the wheel is 24 metres, roughly equivalent to the height of an eight storey building. The structure is located near the Rough Castle Fort and the closest village is Tamfourhill. On 24 May 2002, Queen Elizabeth opened the Falkirk Wheel as part of her Golden Jubilee celebrations.

The wheel, which has an overall diameter of 35 metres, consists of two opposing arms which extend 15 metres beyond the central axle, and which take the shape of a Celtic-inspired, double-headed axe. Two sets of these axe-shaped arms are attached about 25 metres apart to a 3.5 metre diameter axle. Two diametrically opposed water-filled caissons, each with a capacity of 80,000 gallons (302 tons), are fitted between the ends of the arms. According to Archimedes' principle, floating objects displace their own weight in water. This keeps the wheel balanced and so, despite its enormous mass, it rotates through 180° in five and a half minutes whilst using very little power.