|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 tetter-totter. If you have two people of unequal weight, the heavier
person sits closer to the fulcrum to decrease their lever arm.
Making a Weighing
In measuring the mass of any material ,
you must always make.............................................
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 weighings is the mass
of the material.
In weighing an object directly on the pan, you must still make two weighings. The first of
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.