lol... I need help

For science class I got this really tough assignment and I don't even have a clue at all, any ideas or help are welcome. So we have to make a submersible that can either start floating for at least three seconds sink to the bottom and come back up and stay at the top, or start at the bottom go to the top then go back to the bottom. we can't touch the submersible after it's started, use remote controls, can't have anything touching the walls, can't contaminate the tank, or have it attatched to anything outside of the tank. already figured it out on sunday thanks for the help though :]

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whatsisface8 years ago
Tape a coin to a balloon. Blow the balloon up, hold it underwater, let go. It'll rise, then deflate, then fall. Hopefully.
JellyWoo8 years ago
i'm not trying to be mean but you should figure this out yourself. this is your project and not ours.
I dont know if this helps but i used to have these plastic submarines that came out of a cereal box. You would fill it up with baking powder (powder not soda) and the water would cause it to fizz and fill up a small indention full of air. After a few seconds the vessel would turn on its side and release the air pocket and sink to the bottom.
guyfrom7up8 years ago
ooo, how about this: you take a baloon and put it in a water bottle. You blow up the ballon so that if fills up about half of the water bottle. Insert a needle on a cork and put it in the bottle. Make sure the cork is bottom heavy. Put on the cap and drill a tiny hole in it. Put another tiny whole somewhere up the bottle so air can escape. Put it in water, water will slowly fill the bottle. After a while the density (hopefully) will be greater than the water. As the bottle continues to fill when it's at the bottom the needle will press harder and harder onto the baloon. When it blows up it will force the water out and it will rise abrubtly, not giving eough time for all of the air to link therough the tiny airhole. HOPEFULLY, and the densities might not be correct, just what I thoughtup.
ha ha. WE ARE BOTH GENIUSES!!!!!!!!!!!!!!!!!!!!!!!!! (look at my solution above) the simplest ideas are always the best...
Shadowmang (author)  guyfrom7up8 years ago
thats actually a really good idea thanks :]
NachoMahma8 years ago
. Some random thoughts that may give you some ideas: . In the first scenario, you need to have a, say, five second timer that will allow water into the vessel to raise the density enough to sink. . You don't mention a time limit on the bottom, so you could have a mechanical trigger release air from an internal tank to expel the water when the vessel touches the bottom. . How to accomplish that, I don't know. :( There may be better ways to change the density, but using water seems the easiest to me. . The second scenario may be easier to implement, but I can't think of any reason why it would be. . I can't think of a good way to implement my idea without at least one valve that you can open and close multiple times. This will require an onboard power source and some way to control the valve(s).
the simplest ideas are the best... mine was to scotch tape a cork to an open water bottle, and it would sink to the bottom, then the water would weaken the tape, and the cork would float to the top...
ha ha, cool.
i'd get a water bottle and take off the cap. the attach a cork to it with a small amount of scotch tape.
tell your teacher that the cork is the actual submersible.

at first the thing will float, but then the bottle will fill up with water and sink.
the weight of the water inside the bottle will be enough to bring the cork down.
then when the scotch tape is in the water, it will weaken, and the cork will come back to the surface.

this is the best, and simplest idea i could come up with, and i'm positive it will work...
sorry i was late to answer this

good luck!
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