First we put the marbles at the bottom of the glass bottle and we put the cork over. We put the cover and we put the boatinto the water. When can check that the bottle fleets and keep the balance.
We repeated the experiment just viceverse and we can check that the bottle fleets but doesn´t keep the balance.
The glass boat fleet in all cases because its weight (P) is equal to its push(E).
Respect to the balance we should notice the situation of weight and push
When we put the marbles at the bottom the centre of gravity is so down. When the boat inclines it´s generates a couple of strength which makes the boat keep the balance.
When we put the pieces of white cork at the bottom the centre of gravity is so high. When the boat inclines it´s generates a couple of strength which makes the boat doesn´t keep the balance
The more down we put the centre of gravity the more blanced.
by Fernando and Enrique