Why are liquids denser than gases?
153892
because a gas's moleules are all spread out and in liquid they are all together, and a solid is still more dense, because they are packed even tighter together
236269
Because the atoms in heated water are farther apart.  It actually makes the water less dense.  It then becomes easier to freeze less dense liquid.
640568
The density of mercury is greater than the steel ball. Obviously the density of alcohol is less than both the ball and the mercury.
347041
density has to do with the relationship between mass and volume. Water has a density of 1. As long as the mass stays in the same relationship with the volume of water, it has the same density.
109400
Basically... to make more compact or denser. For example to change state from water vapour to a denser liquid state.
668561
Most liquids dilate when heated and therfore the density increases with temperature. Water is an exception below 4 degrees Celsius. The reason are hydrogen bonds.\n\nIn the H20 molecule the hydrogen atoms share their electrons with the oxygen atom in socalled covalent bonds. But the oxygen atom attracts the electrons very strongly and takes more than its share.\n\nAs a consequence the hydrogen atoms form bonds with the oxygen atoms of other water molecules. These hydrogen bonds are weaker than the covalent bonds.\n\nThe result of the existence of hydrogen bonds is that ice is organised in a hexagonal structure which is less dense than water. These structures form already in liquid water too, but to a lesser degree.\n\nThe end result is a tug-of-war between the effect of the hydrogen bonds and the normal dilation of water. With a maximum density at 4 degree C as a consequence.
71290
Solid (frozen) water is lighter than liquid water.  Since low density materials float on higher density materials, ice floats on water.  \n\nSolids are typically poor condutors of heat, so ice forms an insulating barrier between the cold air and the warmer water below.  This insulating effect is what keeps lakes from freezing solid.\n\nIf ice was denser than water, ice would sink and liquid water would rise up to contact the freezing air above.  Even the deepest of lakes and rivers would freeze solid.  Life as we know it could not exist over most parts of the earth.\n\nIt is important to remember that most solids are denser than their melted (liquid) forms.  Water is very unique.  Since we cannot imagine life without floating ice, scientists are looking for water in the cosmos as signs of places that we, or other beings might be able to inhabit.
775748
1. measure the density of the unknown substance.  Compare with published lists of the density of known substances.\n\n2. In general, but not always, solids are more dense than liquids which are more dense than gases.
194414
Water is denser than air and transfers heat more rapidly.
1178623
solid's particles are compact, while on liquids they are loose but gas' are the most loose (more distances with each other)
801001
Ok, this is a weird question, but here's my best answer.  The 2 liquids stay separate because of density.  The green liquid is cooler and contains salt, both of which increase its density.  The red liquid is warmer (its molecules are moving faster and are farther apart) so it's less dense and should float on the denser green solution (unless you shake them, which is why the card method is used).
190514
Density of matter is the reason anything floats.  Any object that displaces its own weight will float. Salt water raises the density of water. Consequently any object will float easier in salt water because it only has to displace little weight compared to non salt water
17452
Hot air is less dense than cold air, assuming that volume is held constant, because the molecules in the heated air move more and faster than in cold air.  Think about a room filled with people.  If the people move around quickly (as molecules in heated air), then the people will spread out more and make more room between eachother (which would be lower density).  Since the hot air is less dense, and more dense objects are "more affected" by gravity, then the warm air is "lighter".
851515
the easy answer is that it is less dense, but if you want the real answer, it is most dense at 4C, here is a graph\n\nhttp://www.piercecollege.edu/offices/weather/water.html
426143
Ice floats on water because it is less dense than water.\n\nAs water cools past 5 degrees celsius, the density of the water actually decreases.  Since ice is water molecules at <0 degrees celsius, it is less dense than liquid water ( greater than 0 degrees), so it floats.\n\nfrom a molecular point of view, the H2O molecules in ice is equally spaced apart, whereas H20 in liquid state are able to slide past each other (i.e. closer to each other), so it is more dense than ice.
102929
Density is the mass per volume.  Buoyancy is the comparison of an object's density with the density of the surroundings.  Helium balloons rise being lifted by the surrounding air sinking around them.  They are less dense than the air they displace, hense are buoyant.
698314
Entropy would increase because when a solid goes to liquid there is more disorder.  They were be more energy because molecules in a liquid move alot faster than in a solid.