Density Quiz

PDF page 489: Which weighs more, a ton of feathers or a ton of bricks? This old riddle plays with the distinction between mass and density. A ton is a ton, of course; but bricks have much greater density than feathers, and so we are tempted to think of them as heavier. (See Figure 11.3.) Density, as you will see, is an important characteristic of substances. It is crucial, for example, in determining whether an object sinks or floats in a fluid. Density is the mass per unit volume of a substance or object. In equation form, density is defined as

PDF page 490: Density is mass per unit volume.

PDF page 490: In the riddle regarding the feathers and bricks, the masses are the same, but the volume occupied by the feathers is much greater, since their density is much lower. The SI unit of density is , representative values are given in

PDF page 491: FIGURE 11.3 A ton of feathers and a ton of bricks have the same mass, but the feathers make a much bigger pile because they have a much

PDF page 490: Table 11.1. The metric system was originally devised so that water would have a density of

PDF page 490: , equivalent to . Thus the basic mass unit, the kilogram, was first devised to be the mass of 1000 mL of water, which has

PDF page 490: , equivalent to . Thus the basic mass unit, the kilogram, was first devised to be the mass of 1000 mL of water, which has

PDF page 490: a volume of 1000 cm .

PDF page 489: Which weighs more, a ton of feathers or a ton of bricks? This old riddle plays with the distinction between mass and density. A ton is a ton, of course; but bricks have much greater density than feathers, and so we are tempted to think of them as heavier. (See Figure 11.3.) Density, as you will see, is an important characteristic of substances. It is crucial, for example, in determining whether an object sinks or floats in a fluid. Density is the mass per unit volume of a substance or object. In equation form, density is defined as

PDF page 490: Gold 19.32 Mercury 13.6 Hydrogen

PDF page 491: lower density. As you can see by examining Table 11.1, the density of an object may help identify its composition. The density of gold, for example, is about 2.5 times the density of iron, which is about 2.5 times the density of aluminum. Density also reveals something about the phase of the matter and its substructure. Notice that the densities of liquids and solids are roughly comparable, consistent with the fact that their atoms are in close contact. The densities of gases are much less than those of liquids and solids, because the atoms in gases are separated by large amounts of empty space.

PDF page 491: lower density. As you can see by examining Table 11.1, the density of an object may help identify its composition. The density of gold, for example, is about 2.5 times the density of iron, which is about 2.5 times the density of aluminum. Density also reveals something about the phase of the matter and its substructure. Notice that the densities of liquids and solids are roughly comparable, consistent with the fact that their atoms are in close contact. The densities of gases are much less than those of liquids and solids, because the atoms in gases are separated by large amounts of empty space.

PDF page 491: lower density. As you can see by examining Table 11.1, the density of an object may help identify its composition. The density of gold, for example, is about 2.5 times the density of iron, which is about 2.5 times the density of aluminum. Density also reveals something about the phase of the matter and its substructure. Notice that the densities of liquids and solids are roughly comparable, consistent with the fact that their atoms are in close contact. The densities of gases are much less than those of liquids and solids, because the atoms in gases are separated by large amounts of empty space.

PDF page 492: The volume of the reservoir is its surface area times its average depth :

PDF page 492: Strategy We can calculate the volume of the reservoir from its dimensions, and find the density of water in Table 11.1. Then the mass can be found from the definition of density

PDF page 492: Solution Solving equation for gives .

PDF page 490: Ethyl Iron or steel 7.8 0.79 Helium alcohol