what is density and what does it have to do with floating?

Question

I have a science quiz and these are two questions I need an answer for.I need to know what is density? And what does it have to do with floating?

Answer 1

Density= mass / volume, or in words, how closely packed the molecules are.



The density of water is 1g/ml



Objects with a density less than 1 will float, greater than 1 will sink.



.

Answer 2

Julia is mostly right. Density is the measure of mass per unit volume, typically grams per cubic centimeter (g/cc), but sometimes lbs per cubic inch or other units.



There are two aspects of floating... floating/sinking of solid objects vs floating/sinking of hollow objects. Technically, an object will float in water if it displaces a larger mass of water than it's own mass. If the object is solid, then the volume it displaces is directly related to the density of that solid. If the object is hollow, like a boat or a balloon, then it is not directly related to the density of the material it is made of. Both aluminum and steel are more dense than water but a great many boats are made of aluminum and steel and they float quite well.



Quite conveniently, liquid water at room temperature is close to 1 g/cc. Suppose you have a cube of aluminum that is exactly 1 cm x 1 cm x 1 cm = 1 cubic cm or 1 cc. Since the density of Al is 2.7 g/cc, that cube will sink in water because the cube weighs 2.7 grams (because it is 1 cc) and an equal volume of water (1 cc) only weighs 1 g. So... the cube does not displace more mass than it's own weight and it sinks. If the cube is made of cork with a density of 0.4 g/cc, then it will float, because, even if it were entirely submerged, it would displace 1 g of water but it only weighs 0.4 g so it floats.



Hope this helps

Answer 3

Density is the amount of mass in a given volume of an object. If an object floats, it is less dense than what it is in. If it sinks, the object is more dense that what it in in.