Why do ships weighing thousands of tons not sink in the ocean? And why do planes so heavy can fly in the air?
397031
Archimedes LAW of buoyancy states that any body completely or partially submerged in a fluid (gas or liquid) at rest is acted upon by an upward, or buoyant, force the magnitude of which is equal to the weight of the fluid displaced by the body.. also, the density of the ship( and the air inside it) is lesser than the density of water. \n\nBernoulli's principle explains why airplanes fly: air/water traveling at faster speed has lower pressure in it.\nthe shape of the airplanes wing is like half of a water drop. therefore the air flowing at the top/above the wing of an airplane is faster compare to the air underneath creating enough pressure to lift the airplane.
2148
Methane gas from the ocean floor..in large amounts..it can cause a tanker size ship to sink in less than 10 seconds..it can cause..plane instruments to read you are climbing in altitude when they are not....1% methane gas in the air is enough to cause a plane engine to stop running instantly.. thus planes crashing ...it has been looked into very well ..I agree..with that theory.
1005012
Maybe it has something to do with grounding. If a ship is in the ocean and not touch anything then there is no reason for the current to go up right?
433856
Perhaps you can picture it this way.  Take your 2,000 ton ship and melt it down and use it to make a very large solid steel cube.  Mearsure the cube and obtain an equal cube of water (say frozen into ice?).  Place the two cubes on opposite ends of a giant seasaw.  The steel cube weighs more than an equal volume of water and goes down (sinks!).\n\nTake a second identical steel cube and build a typical ship.  While still in drydock, fill the inside of the ship with water up to the intended water line (based on an identical ship?).  Drain the water out and use it to make another really giant ice cube.  This ice cube will now be much larger than the cube of steel.  Now place the steel cube and the ice cube on the seasaw.  The weight of the water goes down and the steel cube goes up (floats).  The weight (volume) of the water inside the drydocked ship is equal to the weight of water displaced by the ship (shoved aside by the floating ship) and acts upwards on the bottom of the ship with the same force it had on the seasaw.  It is more than enough to make the ship float unless the ship is loaded up until water flows over the side of the ship and floods it.  Hope that helps a little.
307036
The clouds hang in the air due to buoyancy (density of water vapour is less than air). At higher altitudes the air becomes thinner and force of buoyancy is lesser. so they cant hang at higher altitudes.
296573
There are several reasons gliders are able to fly the way they do:\n\nFirst, gliders are incredibly lightweight and are constructed from lightweight and strong materials, such as fiberglass.\n\nSecond, the wings on a glider are larger than a conventional plane's. This allows the glider to get more lift, which is what keeps conventional planes afloat.\n\nThird, the design of gliders plays a large part in their ability to fly. While conventional planes use thrusters and engines and can simply apply more power to stay afloat, gliders must rely on their superior design to minimize drag.\n\nAside from that, there are other factors at play, such as mother nature. Flying a glider -- just like flying a plane -- requires skill, and any good glider pilot will know how to balanace speed to get more lift when needed.\n\nI hope this helps.
181081
That is a very good question.  The weight of the fly is inside the airplane whether it lands or not.  When I asked a similar question years ago, I was told that the weight of the fly is transfered to the surface under it while it is flying.  I then asked: "If that is true, how come when a huge airplane flys over my head I'm not crushed?"  They answered because the weight is dispersed over a large area of the earth.  I don't understand any of that physics stuff.  I will look forward to checking back to see if some egghead will explain it for us.  Good luck.
972208
I watched a very interesting show that proposed a theory about ships vanishing.  He also gave a very convincing demonstration.  He believes a ship can be sunk immediately if the earth beneath the water was to "Burp" huge amounts of Methane.  This occurrence has happened in a lake in Africa which killed off an entire village.   \n\nHe demonstrated how this would work (in a lab).   He had a huge tank filled with water, that enabled him to have tiny bubbles be emitted from the bottom, with a model ship floating above.  As soon as the tiny bubbles reached the ship, it sank immediately to the bottom.  It showed that the people on board would not have time to call for help.   Air (or Methane gas) will reduce the buoyancy of the ship and sink it.   \n\nSo, this could explain how a ship could vanish without a trace or getting an SOS before it sank.   As for the planes, well, they do fall from the sky for many reasons, and the Ocean (even just the Bermuda Triangle) is a pretty big area.\n\nI was Aircrew in the Navy, and had been on Search and Rescue missions in that area. . .I have to tell you, when we were searching, we never found anyone. . .it was very difficult to see anything.\n\nPlease. . . Vote. . .
258592
Both above answers are correct. Additonally, it cost alot more to do it in the air. You have to spend a lot of fuel getting that tanker plane up to altitude and to where it needs to be. Not to mention pay for the pilots and ground crew support for the tanker plane, storage etc. In contrast You one low pay grade person can drive a tanker truck and fuel planes on the ground.
1007361
The reason you floated better in the ocean is because the density of salt water is different than regular water. \n\nThink about keeping your hips high. If you're on your back, press the back of your neck/head to the bottom. If you're on your stomach, it's very natural for your legs to sink slightly. Just keep your hips up!
193750
This is due to the seawater having a greater heat capacity than the land, thus they heat and cool off at different rates, causing pressure differentials in the air above them. See the source for details.
1123435
Hi, its not gravity but a force opposite to gravity that prevents a boat from sinking and keeps an airplane in the air. Sorry, but I forgot the name of the force, I think it begins with a B. O, the second person said it- Buoyancy.
123066
Because there is no air, yet at the same time they need to hit the air so they can get lift for a soft landing.  The problem is that the air that does exist at such high altitudes is so sparse that it doesn't have the density to provide the lift, so it ends up hitting the craft at a super fast speed which heats it up.  Eventually however, the air is dense enough to provide the lift that it needs.
289385
Denser materials can "float" in the sense of remaining suspended, if they are small enough; think of candle soot. The particles must be small enough so that their fall rate is dominated by their air resistance rather than their weight. Such floating is also helped by brownian motion.
102873
Archimedes Principle.  The bouyant force pushing up on an object in a fluid is equal to the weight of the fluid displaced by the object.  So as long as the ship displaces more than its weight in water, it will float.  This is why ships made of steel and other dense materials tend to be very big and hollow.
65763
Because a ship has surface area, a needle doesn't. Water can flow around it, so it sinks.
847274
OK, compare the oceans to the air.  Which takes up more space?  Air is less dense than water, so the same mass takes up more volume.