| When I was a tot, we had these baking powder submarines. There was a little "bell" on the bottom, under a mesh-bottomed chamber. You put baking powder (powder, not soda) in the chamber and put the sub in the water. It would sink at first. Then the baking powder got wet and started making gas. A gas bubble formed in the bell, lifting the sub to the surface. When it got to the top, it would tip, releasing the gas bubble and sinking. The process would repeat until the baking powder ran out. Part of the trick is making the sub a little top-heavy so it will tip over when it reaches the surface. I think if you google "baking powder submarine" you'll find some directions. |