Janka hardness test understand which woods are harder than others. Janka hardness test The Janka hardness test (from the Austrian-born emigrant Gabriel Janka, 1864-1932) measures the resistance of a sample of wood to denting and wear. It measures the force required to embed an diameter steel ball halfway into a sample of wood. A common use of Janka hardness ratings is to determine whether a species is suitable for use as flooring. The hardness of wood varies with the direction of the wood grain. Testing on the surface of a plank, perpendicular to the grain, is said to be of "side hardness". Testing
Draize test are removed with sticky tape), then covered with plastic sheeting. According to the British Research Defence Society, the Draize eye test is now a "very mild test," in which small amounts of substances are used and are washed out of the eye at the first sign of irritation. In a letter to "Nature", written to refute an article saying that the Draize test had not changed much since the 1940s, Andrew Huxley wrote: "A substance expected from its chemical nature to be seriously painful must not be tested in this way; the test is permissible only if the substance has