space engine that uses gravity as fuel by enlarging and reducing size,like a sub

[gameleaper]

Gameleaper,

there is still MASS in space. Gravity needs MASS, not weight. Your space balloons won't have much mass. It won't matter how big you blow them up.

Ships in a harbour will move towards eachother but we don't know why

Ships alongside each other are pulled together because of the flow of water between the ships which causes a decrease in pressure.

the water would always all be the same pressure, the boats as they move are attracted by some unknown force, they don't drift random or away from other boats they drift towards each other, but I think they have to be big for it to happen

[Barthheart]

Gameleaper,

there is still MASS in space. Gravity needs MASS, not weight. Your space balloons won't have much mass. It won't matter how big you blow them up.

Ships in a harbour will move towards eachother but we don't know why

Ships alongside each other are pulled together because of the flow of water between the ships which causes a decrease in pressure.

the water would always all be the same pressure, the boats as they move are attracted by some unknown force, they don't drift random or away from other boats they drift towards each other, but I think they have to be big for it to happen

Man you really need to stop eating those mushrooms..... 

There is no unknown force drawing ships together, and it isn't gravity either.

You really can't be this dim.... so are you just trolling us for shits and giggles?

[mirth]

https://en.wikipedia.org/wiki/Bernoulli%27s_principle

[Barthheart]

Man... I hate the Bernoulli brothers....  :P

[mirth]

Weren't they the hosts of Car Talk?

[Barthheart]

 ;D

[BanzaiCat]

Barth, you're working on an aneurysm. You need to stop reading these threads! 

[mirth]

I thought Canucks were always supposed to be polite.

[BanzaiCat]

[mirth]

^Savages!