The Floating Tin Sponge

Create a floating tin sponge that rises to the surface upon reaction of an acidic tin(II) chloride solution with zinc. Two distinct single replacement reactions are clearly visible in this demonstration of the activity series of metals and the reactivity of metals with hydrochloric acid. Beautiful crystalline tin needles are deposited immediately on the zinc surface and aggregate to give an open, lattice-like arrangement that resembles steel wool. As hydrogen gas is released, the solution effervesces and the tin sponge gradually bobs and rises and finally floats to the surface.