Principle
Ignoring hydrodynamic effects, all ships or boats float because the weight of the water they displace is equal to the weight of the boat (Archimedes' principle). However, many boats are made of materials that are denser than water, meaning that the boat will sink if filled with water. Although it is not required by the rules of the competition, some competitive concrete canoes have concrete mix designs that are less dense than water. They must pass a test in which the canoe is filled with water and pushed below the surface; the canoe must then resurface in order to qualify for racing. This is possible because, unlike normal concrete which uses sand and small rocks, concrete canoes are created with porous aggregates such as Macrolite and microspheres. However, because many teams still design their concrete mixes to be denser than water, in the United States, teams are allowed to insert concrete-covered, non-structural foam pieces in their canoes to make the canoes float after being submerged.
Read more about this topic: Concrete Canoe
Famous quotes containing the word principle:
“We have been here over forty years, a longer period than the children of Israel wandered through the wilderness, coming to this Capitol pleading for this recognition of the principle that the Government derives its just powers from the consent of the governed. Mr. Chairman, we ask that you report our resolution favorably if you can but unfavorably if you must; that you report one way or the other, so that the Senate may have the chance to consider it.”
—Anna Howard Shaw (1847–1919)
“The principle goal of education in the schools should be creating men and women who are capable of doing new things, not simply repeating what other generations have done; men and women who are creative, inventive and discoverers, who can be critical and verify, and not accept, everything they are offered.”
—Jean Piaget (1896–1980)
“Experimental work provides the strongest evidence for scientific realism. This is not because we test hypotheses about entities. It is because entities that in principle cannot be ‘observed’ are manipulated to produce a new phenomena
[sic] and to investigate other aspects of nature.”
—Ian Hacking (b. 1936)