i need to build a submarine that floats for a minute and sinks for 45 seconds plz help me?

Question

i hav to make the sub by myself i cant buy the sub

Answer 1

Kenner toys used to make a diving submarine. But here is one on E-bay which used baking powder to make the sub rise from the bottom.

For more than you every want to know about baking powder subs check out the last link...