Home Science Tools BS-311S Quad Beam Balance Operating Instructions - page 4
Weighing Operation
Place the object to be weighed on the center of the pan and proceed as follows:
1. Starting with the rear beam, move the 100g weight to the right one notch at a
time until the pointer drops. Then move the 100g weight back to the left one
notch.
2. Now with the third beam, move the 10g weight to the right one notch at a time
until the pointer drops. Then move the 10g weight back to the left one notch.
3. Then, move the 1g weight to the right one notch at a time on the second
beam until the pointer drops. Then move the 1g weight back to the left one
notch.
4. Finally with the front beam, nudge the 0.01g weight to the right until the
pointer reaches the zero position.
5. Add up the weight positions on each of the four beams to get the weight of
the object. Read the 0.01g weight on the front beam to the nearest 0.01g.
Your balance has a total capacity of 311g using the weights on the four beams.
Determining Specific Gravity
The model BS-311S balance can also measure specific gravity as follows:
1. Remove the pan hanger and pan and then slide the specific gravity stand up
about 3 inches. (You may have to tilt the front of specific gravity stand upward
slightly until it slides easily.) Then reinstall the pan hanger on the upper hook
of the pan loop. The pan hanger should float freely under the specific gravity
stand and the balance should zero.
2. Suspend the specimen on a thread from the lower hook of the pan loop to
determine the weight of the object in air.
3. Suspend the specimen on a thread from the lower hook of the pan loop into a
beaker or cup of water to determine the weight of the object in water.
4. Calculate specific gravity by the following formula:
Specific gravity = weight in air ÷ (weight in air - weight in water)
5. You can also determine the specific gravity of solids less dense than water
(i.e. they float) using a fishing sinker and the following procedure:
a) Determine the weight of the object in air (see step 2)
b) Determine the object weight in air plus the sinker weight in water
c) Determine the weight of both the object and sinker in water (see step
Specific gravity = a ÷ (b-c)
Limited Warranty
Home Training Tools warrants this product against defects in materials and
workmanship for one year from the date of purchase. During the warranty
period we will repair or replace, at our option, any defective component(s) at
no charge. You will need to return your balance, freight prepaid, to Home
Training Tools for warranty service. Please call 1-800-860-6272 for details.
Page 4