Science Buddies: "Ask an Expert"

We have built a water bottle submarine ("bottled up buoyancy"). We have used weights to help overcome the natural buoyancy but if have any air in the bottle (needed to perform the buoyancy tests) the air ends up at either end and tips the bottle on end. I don't know how I would make a baffle to help keep the air bubble evenly distributed. Any ideas ?

Hello Hohmank,

I'm assuming that you're working on the project described here:

https://www.sciencebuddies.org/science- ... p034.shtml

Did you make the submarine and propeller as described in the project procedure? And are you following the procedure for the buoyancy experiment? If so, I would expect that the submarine would have a nose up or nose down attitude with one of the smaller volumes of water added to the bottle. Larger amounts of water might be expected to level the submarine. I think that these observations may be part of the experiment.

I hope this helps. Please ask again if you have more questions.

A. Norman