Triple Beam Balance Chem 111

Triple Beam Balance

The Triple Beam Balance is a typical mechanical balance. It has a beam which is supported by a fulcrum. On one side is a pan on which the object is placed. On the other side, the beam is split into three parallel beams, each supporting one weight. In measuring the weight of an object, rather than adding additional weights, each of the three weights can be slid along the beam to increase their lever arm. It works just like a teeter-totter. If you have two people of unequal weight, the heavier person sits closer to the fulcrum f ulcrum to decrease their lever arm. Instructions on use 

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The triple beam balance is used to measure masses very precisely; the reading error is 0.05 gram. With the pan empty, move the three sliders on the three beams to their leftmost positions, so that the balance reads zero. If the indicator on the far right is not aligned with the fixed mark, then calibrate the balance by turning the set screw on the l eft under the pan. Once the balance has been calibrated, place the object to be measured on the pan. Move the 100 gram slider along the beam to the right until the indicator drops below the fixed mark. The notched position immediately to the left of this point indicates the number of hundreds of grams. Now move the 10 gram slider along the beam to the right until the indicator drops below the fixed mark. The notched position immediately to the left of this point indicates the number of tens of grams. The beam in front is not notched; the slider can move anywhere along the beam. The boldface numbers on this beam are grams and the tick marks between the boldface numbers indicate tenths of grams. To find the mass of the object on the pan, simple add the numbers from the three beams. As with a ruler, it is possible to read the front scale to the nearest half tick mark. The Triple Beam Balance is a typical mechanical balance. It has a beam which is supported by a fulcrum. On one side is a pan on which the object is placed. On the other side, the beam is split into three parallel beam, each supporting one weight. In measuring the weight of an object, rather than adding additional weights, each of the three weights can be slid along the beam to increase their lever arm. It works just like a teeter-totter. If you have two people of unequal weight, the heavier person sits closer to the fulcrum f ulcrum to decrease their lever arm.

Making a Weighing In measuring the mass of any material, you must always make two weighing! If you use a container to hold the material, you must first weigh the empty container. This weight is called the tare of the container. Then you weigh the container with the material in it. The difference between these two weighing is the mass of the material. In weighing an object directly on the pan, you must still make two weighing. The first o these is to weigh the empty pan! This must be set to read 0.00 g. The triple beam balance has a little knob under the pan which you screw in or out to set the empty balance to read exactly 0.00 g. So, in weighing an object directly on the pan, you must first Zero the balance. Only if the balance is properly zeroed, will it weigh the object correctly.