Interesting Fact A triple beam balance measures the mass and not the weight of an object. Unlike the traditional spring balance which measures weight, the triple beam balance do esn't rely on gravitational force. It is therefore capable of giving the same ma ss reading on the Moon as it would on Earth, even though the Moon's gravity is o nly 1/6th that of the Earth's. In science, especially in the fields of physics and chemistry, accurate measurem ents is a very important criterion for study and experimentation. Many chemical reactions depend upon precise measurement of the weights of the ingredients, wit hout which they simply wouldn't work. For this, several different weighing devic es have been developed over the years. The triple beam balance is one such weighing device, which allows the user to ac curately gauge the mass of an object in grams. It can provide higher accuracy th an a spring-based measuring scale, and has an error margin of only 0.05 gm. Ther efore, it is primarily used as a laboratory apparatus. In the following sections, we shall examine the different parts of the triple be am balance and then take a look at its functioning. Triple Beam Balance Definition The triple beam balance is a measuring instrument comprising a beam supported on a fulcrum. On one side of this beam, is a pan on which the object to be measure d is placed, while on the other side, the beam is split into three parallel beam s, each carrying a known weight and together culminating into a pointer pointing to a fixed scale. The weights are slid on their respective beams until zero rea ding is obtained and a state of balance is achieved. Thus, a triple beam balance enables the user to measure the mass of an object by balancing it with the help of three counterweights of known values. Parts of a Triple Beam Balance Many different models of the triple beam balance have been designed for various specific uses. However, they all retain the following common features. The above diagram represents a typical triple beam balance. Base and Pan The solid metal platform which supports the rest of the parts of the triple beam balance is known as the base. It provides stability to the apparatus while the measurements are being taken. The pan is located on one side of the apparatus and rests on top of the base. It is where the object to be weighed is placed. Adjustment Knob and Pointer The adjustment knob is present on the left hand side of the apparatus, beneath t he pan. It can be turned to attain greater accuracy while measuring the weight o f an object using the triple beam balance. The pointer is present on the right hand side of the triple beam balance. By def ault, it points to zero on a labeled scale. Together the pointer and the scale a re used to ascertain when the beams are at their resting position, and to determ ine when the correct mass of an object has been found. Triple Beams and Riders
As the name of this apparatus implies, the triple beam balance comprises three b eams which are individually used to determine the mass of an object. Each of the se three beams has a weighted rider on it, which the user can slide along the le ngth of the beam to determine the object's mass. When positioned such that the pan is on the left hand side and the scale and poi nter to the right, the beam which is located on the front has a 10 gm scale and a 0.1 gm rider on it. The second beam which is located in the middle, has a 500 gm scale with 100 gm rider on it. The third beam, located at the back, has 100 g m scale with a 10 gm rider. When all three riders are positioned completely to t he right, their combined weight equals 500 gm + 100 gm + 10 gm = 600 gm. This is the maximum weight that the triple beam balance can measure. Triple Beam Balance Function The following steps show how to use the triple beam balance scale for precisely measuring the mass of an object. Step 1 Keeping the pan empty, move all three riders on the three beams to their leftmos t positions. Check the pointer and scale to ensure that it reads zero. If it doe sn't, then calibrate the scale by turning the adjustment knob until a zero readi ng is obtained. Step 2 After calibration, place the object to be measured on the center of the pan. The pointer will move away from the zero reading. Step 3 Slide the 100 gm rider to the left slowly from notch to notch, until the pointer drops below the zero mark. At this point move the rider back a notch. For examp le, if your object weighs 485 gm, then the pointer will drop below zero when the rider is put on the notch representing 500 gm. So you will have to slide it bac k to the 400 gm notch. Step 4 Now move the 10 gm rider from notch to notch in a similar manner as you did with the 100 gm notch until the pointer drops below zero at which point, you must mo ve it back a notch. Again, if your object weighs 485 gm, then your 10 gm rider w ill drop below zero at the 90 gm notch. You are then required to move it back to the 80 gm notch. Step 5 Lastly move the 1 gm rider slowly on its beam until the pointer aligns at zero. Note that this beam doesn't have notches and so, while sliding the rider along i t, you have to keep an eye on the pointer and stop as soon as it reaches zero. T aking the above example, the pointer will read zero when this rider reaches 5 gm . Step 6 Take the total of all the three numbers indicated by the positions of the three riders to get the mass of the object on the pan.
Thus, the triple beam balance can be used to correctly and opular choice in most physics bout its use is essential for
is a very ingenious and user-friendly device, that precisely measure the mass of an object. It is a p and chemistry laboratories, and hence, knowledge a students.
