This has been the means of a number of scientific discoveries both great and small. There are lots of hand soaps out there. Now liquid soaps seem to be very popular. Many are packaged with plastic net scrubbers to work up a lather and exfoliate the skin. Still, one soap is unique.
Ivory soap is different because it floats.
The development of this soap was an accident. In 1879 an absent-minded workman left a stirring machine running all through the entire lunch break. The machine whipped up a huge amount of air into the batch of soap. So much air was added that the soap floated. They hated to waste all of the product, so they processed it and sold it anyway.