Waka reflection

Last week we tested our waka we all built different waka. The easy part was making the design the hard part was holding the coins on my boat. And they were all buoyant until we put coins on we started seeing different waka sink but most that sunk were made out of tin foil and the ones were made out of bottles floated the bottle made boats were less dense so they floated the tin foil was less dense to but they didn't have the support to hold a coin so it sunk here is one of the successful boats. Next time I will make sure my materials are durable and strong