Monday, September 20, 2010

Lab 1-2: Indirect Measurement

In this lab indirect measurement is used to find the diameters and thickness of aluminum foil and copper wire. To determine these values the volume is calculated after finding the mass and density of your object. Mass is found by weighing the copper wire and aluminum foil on a scale and then using its density located in Table S of the reference tables. With these two values i then can use the formula resulting in volume.The volume is crucial to finding the thickness or diameter with the help of length and width. When calculating the thickness of the regular aluminum foil the mass was weighed to about 1.46g this divided by aluminum's density of 2.98g/cm3 equals your volume.Using the resulting volume of .541cm3 you then measures the length and width and the plug the values into the formula V= L x W x Thickness. You then solve for T, the thickness comes out to be .0013cm. You repeat these sames steps for the heavy aluminum foil with different measurements the thickness resulted in .0023cm. The Copper wire uses the same steps for volume but substitutes different values for density and mass pertaining to the copper wire. After measuring the length the copper wires volume .035cm3 and length is then substituted in the formula for the volume of a cylinder. After you solve for "r" (radius) your must multiply this answer by two to get your diameter .064cm. Some methods of indirect measurement are better then others depending on your object. For example the thickness and diameter was to small to measure with a ruler or water displacement so you used indirect measurement of volume.

When calculating the actual thickness of the foil you may end up with a bunch of decimals, this may be a result that is good or bad. The decimals give you a more precise measurement of thickness but also with more numbers you have a higher chance of error. Some sources error may come from rounding values like length to the nearest tenth. A scale is also sometimes imprecise in its measurements and these calculations alter you volume and diameter. Indirect measurement is better for things not used industrially like buildings or bridges that call for exact measurements for stability in structure. Indirect measurement is for purposes when you don't need something precise. An example is if you want to store something in jars and you don't know the jars diameter indirect measurement can be used to find its measurement through volume of a cylinder formula.

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