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According to the U.S. Mint, the thickness of a quarter is 1.75 mm. What tool would you use to measure this thickness accurately?

vernier caliper. Vernier calipers are excellent for measuring this distance. With the advent of digital calipers, micrometers are obsolete, unless you are a diehard and enjoy reading three scales to find one measurement. For this reason, micrometer was not listed as an option. An electron microscope could be used, but the other methods mentioned earlier are more economical. The other two tools are not precise enough to measure to the nearest one hundredth of a millimeter (less than 0.005 inch).

You plan to paint your bathroom and need to know how much paint to buy. What tool will be adequate for the job?

Tape measure or yard stick. A "quick and dirty" estimate can be made by measuring the length, width, and height of your bathroom. Find the areas of the walls and if you want to paint the ceiling, calculate that, too. On each paint can there is an estimate of the number of square feet or square meters that the paint will cover. Since this estimate is based upon perfectly smooth walls, you probably should buy about 50% more to account for absorption by walls and wall roughness. The lady at the Home Depot or other home improvement store may also be able to advise you on how much to buy using your calculated area.

Allen keys (also called Allen wrenches) are used for a variety of applications around the home. What is another name for these small wrenches that describes their shape?

hex keys. These small inexpensive wrenches come in a variety of sizes. There are American and metric sets. The end of the wrench is in the shape of a hexagon, hence the name hex wrench or hex key. There are at least four other names for this handy tool.

What is the best tool to use to measure the distance you walk daily?

pedometer. An accurate pedometer can be of great help when start a walking program for exercise. Avoid cheap pedometers. They will either fall apart or will not be accurate. You can buy a pedometer with many special features for $70, but other models that cost only $20-25 are adequate for most walkers.

A vial of medicine says to administer 0.010 cc per pound of body weight. What tool would you use to measure the dose for a 200 pound person?

a hypodermic syringe. A 200 pound person would require a 2.0 cc dose. Only a hypodermic syringe is capable of delivering this dose with accuracy and precision. A "smidgen" measuring spoon actually exists and it is 1/32 of a teaspoon. A pinch is 1/8 of a teaspoon and a dash is half a pinch or 1/16 teaspoon. One manufacturer even offers a "hint" measuring spoon, claiming it measures 1/64 teaspoon.

How could you measure the inseam length of your jeans?

tape measure. Usually inseam measurements are rounded to the nearest inch or centimeter, so a tape measure is the correct tool. The micrometer, and atomic force microscopy are used for very small measurements and topography.

Now let's use that hammer to pound in some ten penny nails. How long are these nails?

three inches long. In the United States, nails length can be given in pennyweights, inches or both. Pennyweights denoted by the letter d, are related to the length of the nail, not its weight. The origin of the terminology comes from the price of 100 nails of a given length.

Archimedes is said to have run through the streets of Athens shouting "Eureka!" when he realized that he could determine the composition of a gold crown by determining its density. What tools would I need to determine the density of a spherical object that is known to be exactly one inch in diameter?

analytical balance. Density is mass divided by volume. The mass can be determined accurately using an analytical balance. If the object were oddly-shaped we would need to measure displacement. But since we know the diameter of the object, we can divide it by two to find the radius. Calculate the volume of the sphere using the formula V = 4/3 pi r cubed. A calculator is a handy tool to perform this operation quickly.

What tool would you use to view the planet Mars?

telescope. A telescope is used to view large objects and a microscope is used for small objects. The camera obscura is a device used by artists to project an image onto paper, and the outline of the image can be traced. The electroscope responds to positive or negative electrical charge.

You want to attach two pieces of wood using a screw with a 1/16 inch pitch. If you want to drive the screw in one inch, what do you do?

Turn the screw and screwdriver clockwise sixteen complete turns. Each complete turn clockwise advances the screw 1/16 inch into the wood, so the screw must be turned 16 times in the clockwise direction to advance one inch. Counterclockwise turns draws the screw out of the wood.