A triple beam balance is a type of lab equipment used to measure mass very precisely, with a reading error of ±0.05 grams. It consists of three beams, each of which is provided with a single weight, and a pan on which the object to be weighed is placed. The beams are different sizes, with the middle beam being the largest, the far beam of medium size, and the front beam the smallest. The difference in size of the beams indicates the difference in weights and reading scale that each beam measures. Typically, the reading scale of the middle beam reads in 100-gram increments, the far beam in 10-gram increments, and the front beam can read from 0 to 10 grams.
The triple beam balance can be used to measure mass directly from objects, find mass by difference for liquids, and measure out substances. To use the triple beam balance, one should start with the lowest level of precision (e.g., 100-gram increments) and move the sliders on the beams to their leftmost positions so that the balance reads zero. 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. Then 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, and 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, simply add the numbers from the three beams.
In summary, a triple beam balance is used to measure mass very precisely and can be used to measure mass directly from objects, find mass by difference for liquids, and measure out substances.
