h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Family legend has it that my Great Aunt Carrie invented a kind of floating soap back in the 1930's. Considering what a truly wonderful idea that would be, saving all those lost hours searching for a missing bar under the bathtime bubbles, I've always been surprised that a)she didn't patent it, b)she didn't pass the recipe down to the rest of us and c)nobody else seems to have come up with the idea since.
Or have they? Was it all a myth? Is it possible to make soap less dense than water so it would lie helpfully ready on the surface if dropped? If not, why not?

I saw a piece on 'Tomorrow's World' (British science program that looks at new technology / inventions) a few years ago. A man had invented floating soap by finding a way to trap bubbles of air in the soap. It wasn't a case of making the soap bubbly (like Aero), but of creating little capsules of air. The capsules were embedded throughout the soap and would break down when the soap around them had been used. Apparently this was necessary because soap dissolves in water and the inventor wanted to get round that problem.

None of the toiletries manufacturers seem to have taken up his invention, though.

Maybe toiletry manufacturers LIKE dropping the soap.

Someone stole the idea from your dear auntie, I think. Actually, I believe that Ivory soap, commonly known to float (and I just did a little experiment to proove it, just to make sure I wasn't making a fool of myself), has been floating for a very very long time. (Not the same bar of course.) Possibly since the 1800's. But don't quote me on that.

I had a friend who thought he had invented floating soap, so he wrote to a soap manufacturer to try to market his idea. They sent him lots of details of how soap is made and they told him that soap floats naturally and it "floatiness" is taken out. I think it is something to do with the fact that if you let it go, it sinks to the bottom out of sight and you are more likely to forget about it and leave it there dissolving, so that you use more.