how does a ship made of steel and other dence materials float on top of water?
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.
120158
The standard definition of floating was first recorded by Archimedes and goes something like this: An object in a fluid experiences an upward force equal to the weight of the fluid displaced by the object. So if a boat weighs 1,000 pounds (or kilograms), it will sink into the water until it has displaced 1,000 pounds (or kilograms) of water. Provided that the boat displaces 1,000 pounds of water before the whole thing is submerged, the boat floats.\n\nIt is not very hard to shape a boat in such a way that the weight of the boat has been displaced before the boat is completely underwater. The reason it is so easy is that a good portion of the interior of any boat is air (unlike a cube of steel, which is solid steel throughout). The average density of a boat -- the combination of the steel and the air -- is very light compared to the average density of water. So very little of the boat actually has to submerge into the water before it has displaced the weight of the boat.\n\nThe next question to ask involves floating itself. How do the water molecules know when 1,000 pounds of them have gotten out of the way? It turns out that the actual act of floating has to do with pressure rather than weight. If you take a column of water 1 inch square and 1 foot tall, it weighs about 0.44 pounds depending on the temperature of the water (if you take a column of water 1 cm square by 1 meter tall, it weights about 100 grams). That means that a 1-foot-high column of water exerts 0.44 pounds per square inch (psi). Similarly, a 1-meter-high column of water exerts 9,800 pascals (Pa).\n\nIf you were to submerge a box with a pressure gauge attached (as shown in this picture) into water, then the pressure gauge would measure the pressure of the water at the submerged depth:\n\n\nIf you were to submerge the box 1 foot into the water, the gauge would read 0.44 psi (if you submerged it 1 meter, it would read 9,800 Pa). What this means is that the bottom of the box has an upward force being applied to it by that pressure. So if the box is 1 foot square and it is submerged 1 foot, the bottom of the box is being pushed up by a water pressure of (12 inches * 12 inches * 0.44 psi) 62 pounds (if the box is 1 meter square and submerged 1 meter deep, the upward force is 9,800 newtons). This just happens to exactly equal the weight of the cubic foot or cubic meter of water that is displaced!\n\nIt is this upward water pressure pushing on the bottom of the boat that is causing the boat to float. Each square inch (or square centimeter) of the boat that is underwater has water pressure pushing it upward, and this combined pressure floats the boat.
1091717
if the objects not close to any celestial body, it just 'floats'. like a bottle in the ocean.
1122613
You must already understand the displacement description so here's an attempt to physically understand the process.\n\nGravity pulls everything with mass  towards the center of the Earth.  This includes water and even air.  This is what creates air pressure and water pressure within a column of the fluid.  The force towards the center of the Earth is called the Weight.  Weight is simply the mass of an object multiplied by the acceleration of gravity (32.2 feet per second).\n\nMolecules in fluids can move around very easily.  They are constantly being pulled downward by gravity.  Generally, they are blocked by other fluid molecules already below them but they pile up and apply a pressure to the poor suckers below them.  The molecules at the bottom of the stack are under tremendous pressure in very deep portions of the ocean because they have to support the weight of the molecules above them.  (This also creates a sea level air pressure of 14.7 pounds per square inch)\n\nShips weigh less than the water they displace.  Gravity is pulling that ship down, trying to get it to the center of the Earth.  Once the weight of the water equals the weight of the ship, the water pushes back with enough force to keep it afloat.  Water molecules can flow easily.  When they begin to weigh more than the effective weight of the ship, they will flow beneath it and push the ship upward.
622351
to get the foundations over water, there are several ways to get the foundation for the bridge set up over the water.  one way is to float out a platform that is not unlike an oil derrick.  from there 'piles'(columns made out of concrete or steel)are driven down into the ocean floor and a foundation is rested and secured and built on it until you get to the top.  \n\nthe other way is (in shallower water) to build a 'coffer dam'  this is a temporary structure that you would build around the place that you want the foudmnation for the bridge in the water.  you put the dam around the area, pump out the water, and then build a foundation as you normally would, or even place piles like the example from above.
378932
First of all, the word moon-pool is a kind of drilling oil wells in the sea-beds. Since the oil gathering (or collecting) ship has a pool inside to collect all oil from the wells and separate the water below the oil, the pools in entertainment ships sometimes are called moon-pool as they are almost similar in shape.\nSecond, either its structure is a simple space inside the ship board or a specially designed one, the ship can bear the weight completely. It's important to note one thing: the ship itself is made of tons of steel; so why it does not sink? It doesn't make any difference if the weight on ship is due to goods, persons, cargos, or water. As far as the specific gravity of the segment of ship inside the water is equal one (or almost), the ship floats. So the design of lower parts of ships are so that there is a large amount of free space (atmospheric rooms) which balance the weight per volume. A common ship with length of about 50m and height of 3-5m normally can carry loads of about 5000 tons; and the total weight of water in a pool with 15x8x4m dimensions is only 480 tons (i.e. less than 10% of payload)
177066
I cant verify this, but i "heard" that it originated because a polish ship designer had a plan to build ships quicker and cheaper and stronger using concrete. now this was a good idea(ww2 time frame), because ships could just be poured from a mold, and we needed a lot of ships quickly. Well anyway, the people using his design made some form of error and the ship sank, and everyone, not understanding the guys theories, just said "of course it sank, concrete doesnt float" and he was a "dumb polack". again, i cant verify that, it was a story one of my elementary teachers told me.
255960
On old sailing war ships, the steel cannon balls were stacked in pyramid piles. Originally they had a steel base that the cannon balls sat on. They soon realised that in cold weather, the metal balls would freeze to the metal base.\nThey changed the base for Brass, (called a monkey) Due to contraction, The brass base would shrink quicker than the metal balls & the balls would fall off the "brass monkey"
64876
Buoyancy is simple.  If the weight of the liquid moved by insertion of an object into the liquid is greater than the weight of the object, it will float.  That is why the size of ships are measured in displacement.  The "Displacement" refers to the weight of water that is "moved out of the way".\n\nThink of it this way - take two identical spheres with the exact same outer material and thinkness.  One is hallow, and one is filled with lead.  Of course, we know that the one filled with lead will sink?  Why?  Because it weighs more than the water that is being moved out of the way.  How do you make it neutrally bouyant?  Simply fill it with enough lead that equals the weight of the water displaced by the sphere.\n\nThis is called Archimedes Law of Bouyancy.  Google/Yahoo search it and you should find some illustrations to help explain.
823430
the buoyancy of the object and its volume.
795940
Density has to do with the physical makeup of a given object. Buoyancy is the property of displacing water in being able to float. The reason a large steel carrier can float in the water is due to its density characteristics and the resulting floating properties as expressed in its buoyancy. The fact that the ship being a steel shell, weighs less than the amount of displaced water, therefore resulting in the resistance of the water causing the steel superstructure to float. \n\nDarryl S.
689832
The object must be less dense than the fluid to float, and more dense to sink.  If it is exactly equal density, then it can be suspended.
255989
A stationary body submerged in a liquid is effected by two forces, gravity and buoyancy. Gravity acts at the center of mass and it is always directed straight down. On a rigid body, the center of gravity can be considered stationary in reference to the body. Buoyancy, on the other hand, acts at the center of buoyancy, and the center of buoyancy moves as the body tilts and rolls. The size of the gravity force is;\n\nFg = Mass * Gravity\nThe size of the buoyancy force is proportional to the volume of liquid that it displaces, the force of gravity and the density of the liquid.\n\nFb = (Volume * LiquidDensity) * gravity\nWhen an object is stable in the liquid, the gravity force and the buoyancy force cancel each other out. This means that the boat is displacing an amount of liquid that weight as much as the boat does itself.\n\nFg = Fb
80144
Center of gravity of the displaced liquid is the center of bouyancy. The (resultant) weight of the vessel acts at the center of gravity(downwards) and the (resultant) bouyant force acts at the center of bouyancy upwards.\n\nIt is better to have the center of gravity lower than the center of boyancy. for stabality. The lower it is the more stable.\n\nThis is because, if the vessel is tilted, the weight and the bouyant force make a couple. This can be against the tilt or with the tilt. If center of bouyancy is lower than center of gravity, it will tilt more. And vice versa.\n\n YOu can find this out by drawing small diagram of the forces.\n\nAlso you can try this. \nTake a pencil. \nhold it vertical but little tilted. \nnow assume, the bottom end is center of bouyancy and top end is center of gravity.\n\nso, push up form the bottom and push down form the top. You will see that the pencil becomes horizontal. i.e you ship sinks.\n\nIf you assume the opposite - take the top to be the center of bouyancy. Pull the top up and the bottom down. The pencil straightens. YOur ship stabalises.
67818
Its all BUYOANCY force.which keeps ship floating.
149208
I believe that a "floating ground" is used on large seagoing ships (pun intended!).  Seriously, the floating ground avoids using the ship's structure including the hull from carrying large electrical currents that may promote corrosion.  Often sacrificial zinc plates are also placed on the hull to avoid galvanic corrosion, especially because the properrers are bronze and the hull is steel.  With a floating ground system, electric supply cables must also include sufficient ground wires to permit current to flow between the ship's generators and all loads and back to the generators.  The frames of machines and electronic devices must also use the floating ground system to avoid shocks to the crew.
432420
jeez - that sounds a demanding course.\nmake a paper boat in the style of an old galleon and stick a coin in the bottom. It will stop it falling over and demonstrate how the galleon can transport gold without sinking.\nThat should give you an E instead of F.