I have to make a toy submarine for school. Does anybody know how? or ideas would

[?soccer?]

be great too.? The submarine either has to start at the bottom of the water and go up, then down, then up, or start from the top of the water and go down, then up, then down..
If you have done this before, how did you do it?? it`s due tomorrow!!

[injanier]

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.