Torbal DK1 Density Determination Guide - Manual (Page 2)

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MAKING THE MEASUREMENTS
Determining the Density (Specific Gravity) of Solids with density >1.
Be sure that the sinker and suspension wire have been cleaned before starting. Distilled water will be
used as the fluid. Two drops of dishwasher detergent may be added to reduce meniscus effects for
optimal results. Center the 400ml beaker on the beaker support frame so that it is centered under the
suspension wire for the sinker (sample holder assembly). Attach the thermometer to the retaining
bracket and place in the beaker. Fill the beaker to the 400ml level.
Determining Wd (Dry Weight)
1. Tare the balance
2. Place the sample on the upper frame pan (not the Sinker).
3. Record the result (Wd)
Determining Ww (Wet Weight)
1. Tare the balance
2. Place the sample on the Sinker (wet sample holder). Best done with forceps.
3. Record the result (Ww)
Determining the Temperature
1. Read the temperature from the thermometer to the nearest 0.1 C
2. Record the result
Calculating the Density
1. Enter the 2 or 3 values recorded above into the appropriate cells in Torbal Density Calculator
spreadsheet running in Excel on a standard PC, or
2. Use the spreadsheet formula furnished above where Dw must be obtained from a table, Dair can
be approximated at 0.0012 g/cubic cm, and Kimmersion = 0.99989 for the 400ml beaker.
Remember that Buoyancy = Wd - Ww
Determining the Density (Specific Gravity) of Solids with density <1.
Same as above, only when determining the Ww place the sample under the Sinker (wet sample
holder). This is the application where the name “Sinker” makes sense. If the Sinker is not heavy enough
to hold the sample down simply add weight to the Sinker pan and start over from the beginning.
Determining the Density of fluids
Determining the volume of the Sinker (this need only be done once)
1. With the beaker empty and the Sinker in place on the support wire, Tare the balance.
2. Fill the beaker with distilled water to the 400ml level.
3. Record the negative weight reading (which equals the buoyancy of the sinker and the small
piece of support wire which is immersed).
4. Record the fluid temperature to the nearest 0,1 C
Calculating the volume