Where are more people per space, NYC or the Smokie Mountains?

DENSITY MAP 3.1 Population density in 2000 from GPWv3 adjusted to UN totals

What two values must be determined to calculate density? MASS VOLUME

MASS Amount of matter (particles) in an object. Instrument: balance Units: grams (g) How is mass different from weight? Weight accounts for gravity AND Gravity depends on the mass and distance of the two objects.

Volume The space an object occupies Instrument: ruler or graduated cylinder Units: centimeter cubed (cm3) or milliliter (mL)

Volume Cubic solid Equation Irregular solid Displacement method Length x width x height Irregular solid Displacement method Volume of a cylinder? Volume of liquid? How is area different from volume?

Density of materials

COMMON MATERIALS Water ………………………1.00 Glass………………………2.60 Granite……………………...2.650 Bone……………………….1.85 Human Body………………..0.995 Butter……………………...0.94 Ice…………………………...0.917 Carbon…………………….2.60 Kerosene……………………0.800 Chalk………………………2.36 Salt………………………….2.200 Coal………………………..1.50 Sand…………………………2.800 Cork………………………..0.25 Sulfuric Acid………………..1.840 Gasoline……………………0.72 COMMON METALS Aluminum…………………..2.70 Mercury……………………13.60 Brass………………………...8.40 Nickel………………………8.80 Chromium…………………..7.10 Platinum……………………21.50 Copper………………………8.63 Silver……………………….10.40 Gold…………………………19.30 Tin………………………….7.30 Iron………………………….7.80 Uranium……………………18.70 Lead…………………………11.30 Zinc…………………………6.90 Magnesium………………….1.74 SOME COMMON WOODS Alder………………………0.40 White Pine…………………0.43 Ash………………………..0.75 Maple………………………0.69 Balsa………………………0.12 Oak…………………………0.85 Douglass fir……………….0.56 Yellow Pine………………...0.46 Ebony……………………..1.20 Walnut……………………..0.67 Larch (tamarack)………..0.51 http://www.iem-inc.com/tooldens.html Apples - 0.641

Density DENSITY = mass volume Density is one of the best physical properties for determining what material it is! Regardless of size or shape, for a uniform material, density does not change at constant temperature and pressure. example: A brick of gold or a small nugget of gold might have different masses and volumes but the density does not change!

M V D Density Triangle DIVIDE Multiply Example#1 Mass= 25g, volume =5mL Example#2 Density =5 g/mL Volume= 10 mL M mass DIVIDE Density = 5 g/mL Mass= 10 g Multiply V D Volume Density So, d=m/v and v=m/d and m=d x v

Density facts Most materials are most dense in the solid phase. But water is most dense in the liquid phase. If you increase the temperature of a material, the mass stays constant, the volume increases, and the density decreases. Increase the pressure on a material and the mass stays constant, the volume decreases, and the density increases.

                                                                                                                    Figure 3. Relationship of water temperature to density for distilled water

Steps in Determining DENSITY OF A LIQUID Find the mass(in grams) of an EMPTY graduated cylinder using electronic scale. 2. Pour an amount of the sample liquid into the same graduated cylinder. Find the mass(in grams) of the graduated cylinder AND the liquid TOGETHER. 4. SUBTRACT to find the mass of the liquid ALONE. Read the volume of the liquid (in mL) in the graduated cylinder. 6. Put the values into the density formula: Density = ________g = mL _________g/mL