Which floats better low density or high density substances?

Answer 1

Because if you look at the volume it occupies the ship will still weigh less than the same volume of water. The Greek scholar Archimedes realised when he was taking a bath what is now called his 'Law'. It is said that he ran into the street naked shouting "Eureka!" (I've found it!), although this is a legend. In his bath he realised that when an object is placed in water it experiences a force upwards (an 'upthrust') equal to the weight of water it displaces. If the upthrust is more than the weight of the object pulling downwards, the object floats. If the upwards force is too small to counteract the downwards weight of the object, it will sink.

Because of its shape, even though a ship is made from dense materials, it still displaces enough water to create an upthrust larger than the weight of the ship, so it floats. However, if you somehow crushed the ship into a block, although it would weigh exactly the same, because it displaced less water, it would sink.

Answer 2

Generally speaking, no. To float, the mass of the floating object has to be equal to the mass of the fluid displaced by that object. Therefore, a steel ship can float on water (even though steel obviously has a density greater than that of water) because the amount of water displaced by the ship (the steel hull and the air inside the hull) is equal to the total mass of the ship. That's the general rule, however there are exceptions. Surface tension in fluids (most notably in water) can be great enough to support some objects of greater density. Note the floating coin demonstration (http://www.YouTube.com/watch?v=uPJRbFW8Nm4).

Answer 3

Yes, to float, an object must have a net density less then the surrounding water. Although a ship is heavy, the majority of the hull holds huge amounts of air. These pockets of air counteract the ship's density, giving the ship a net density low enough that it can float.

A good illustration of this is with tin foil boats. A tin foil boat will float because the air/boat ratio of the design allows room for more than enough air to counteract the density of the foil. However, if you filled the space that contained the air with water, the ship would sink because there would be no more air left to counteract the foil's density. Plus, you had the additional density of the water.

If you do the math:

Densities:

Air = 1.2 kg/m3

Steel = 7850 kg/m3

Water = 1000 kg/m3

Now assuming that the boat is 100 meters x 100 meters x 1 meter:

Net force the ship is exerting on the water: 2,272,800

Net force the water pushing back: 10,400,000

As you can see this ship will definitely float, because the water is exerting more force than the boat, so the water will end up "pushing" the boat to the surface.

Answer 4

Low-density substances float better than high-density substances. This is because low-density substances are less dense than the fluid they are placed in, causing them to float on the surface. High-density substances are more likely to sink in the fluid because they are denser than the fluid.

Answer 5

Relatively speaking, all water vessels float upon water of the same density.

Answer 6

False...if it had a greater density, it would sink. Less dense materials float.

Answer 7

If something floats in a substance, it means that it is less dense than the substance it is in. If it were more dense, it would sink to the bottom.

Answer 8

Low density substances.