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I have this idea in my mind for a while now and it seems great subject to share it with you. Imagine an elevator going kilometers into the oceans dept. A huge

I have this idea in my mind for a while now and it seems great subject to share it with you. Imagine an elevator going kilometers into the oceans dept. A huge tank is mounted on the top of it. It gets filled in with pressurized air. Because its heavy it sinks to the bottom. Then an air is released. Air travels into the surface but on its way it is actually captured into a little traps. When enough air is trapped, the entire structure built from hundreds of traps is lifted into the surface, together with the tank. of course during this trip, it triggers friction and the dynamo mounted on the surface translates this movement into electricity. Once on the surface, the tank is filled in with air, and the process starts all over. With long enough elevator in deep enough ocean, the electricity produced thanks to the travelling elevator would be greater than electricity used to put air into the tank. If you ignore the rules of gravity and that trapped air travels to the surface of a water, this could be a perpetuate mobile. What's wrong with my idea?

jakobegger 12y ago
The deeper you go, the higher the pressure. The higher the pressure, the smaller the (trapped) air bubbles. The smaller the air bubbles, the lower the upward force. As a result, the deeper you go, the more air you will need to pump into your tank. Or in other words: with a given amount of air inside your tank, there's a maximum depth you can go. If you go deeper, the air bubbles will no longer lift the tank.
- joering2 12y ago
  Of course, and that's what happened to Kursk. But: The released air would go up, regardless how pressured it is. While going up it would decompress taking up more space and therefore having greater force to push the tank up (as I mentioned, released air would be capture in a construction similar to a tree with leaves. Imagine leaves upside-down capturing the air. I'm sure you can find different type of mix that would be less-compressible and overal better for this experiment.
  - jakobegger 12y ago
    If the bubbles are captured higher up, say 500m above the tank, so that the increase in deplaced water can lift the tank, you couldn't lift the tank all the way up to the surface; it would be stuck at 500m below surface. It's the basic law of conservation of energy. You need to provide the energy required to lift the tank by compressing the air. The energy required to lift the tank is mgh (mass of tank, gravitational constant, height to lift the tank). The energy stored inside the tank is proportional to p*V (pressure times volume). You can't lift the tank further than the amount of energy you have available, so you can never have a surplus of energy.

jakobegger 12y ago

The deeper you go, the higher the pressure. The higher the pressure, the smaller the (trapped) air bubbles. The smaller the air bubbles, the lower the upward force. As a result, the deeper you go, the more air you will need to pump into your tank. Or in other words: with a given amount of air inside your tank, there's a maximum depth you can go. If you go deeper, the air bubbles will no longer lift the tank.

joering2 12y ago
Of course, and that's what happened to Kursk. But: The released air would go up, regardless how pressured it is. While going up it would decompress taking up more space and therefore having greater force to push the tank up (as I mentioned, released air would be capture in a construction similar to a tree with leaves. Imagine leaves upside-down capturing the air. I'm sure you can find different type of mix that would be less-compressible and overal better for this experiment.
- jakobegger 12y ago
  If the bubbles are captured higher up, say 500m above the tank, so that the increase in deplaced water can lift the tank, you couldn't lift the tank all the way up to the surface; it would be stuck at 500m below surface. It's the basic law of conservation of energy. You need to provide the energy required to lift the tank by compressing the air. The energy required to lift the tank is mgh (mass of tank, gravitational constant, height to lift the tank). The energy stored inside the tank is proportional to p*V (pressure times volume). You can't lift the tank further than the amount of energy you have available, so you can never have a surplus of energy.