CE En 270 - Homework #6
Hydrometer Analysis
(Note: You can do either this problem or the vector problem for HW#6. You do not need to do both)
A hydrometer analysis is a test done on a soil sample to determine the particle size distribution for the smaller fraction of the soil particles. It involves mixing the soil with water in a glass beaker and measuring how rapidly the particles settle out of the solution. The density of the solution changes with time as the particles settle to the bottom of the beaker. The following spreadsheet is designed to analyze the results of a hydrometer test:
Right click here to download a copy of the spreadsheet and enter the formulas for the empty cells shown in light blue according to the following directions.
Before entering the formulas, first name the cells at the top of the spreadsheet as follows. Use these names in your formulas.
| Variable | Cell | Name |
| Dry weight of sample | G4 | Ws |
| Specific gravity | G5 | Gs |
| Temperature (oF) | G6 | Tf |
| Temperature (oC) | G7 | Tc |
| Meniscus correction factor (Fm) | G8 | Fm |
| Zero correction factor (Fz) | G9 | Fz |
| Temperature correction factor | G10 | Ft |
| Stoke's law coefficient | G11 | A |
| Specific gravity correction factor | G12 | aa |
| Table index table | K6:L12 | indextable |
| Stoke's Law coeff. table | K19:R32 | stokestable |
a. Enter a formula in cell G6 to convert the temperature from oF to oC.
b. Enter a formula in cell G9 to compute the temperature correction factor (FT).
c. Enter a formula in cell G10 to compute Stoke's law coefficient (A). To do this, you will need to use a lookup table to get the A coefficient corresponding to the temperature in oC. The table you will use is Table 2.1 that begins in column K. To use this table, you will need to do a "double lookup". You will pass the Gs value to the Index Table to find the column index corresponding to the value of Gs in in cell G5. You will then use this value to lookup the proper A coefficient depending on the temp. In other words, you will used a VLOOKUP function for the index embedded within a VLOOKUP function for the A coeff. Do not expect your lookup references to find an exact match on either Gs or T. Do a range lookup in either case.
d. Enter the formula for the Percent fine (Pf) column.
e. Enter the formula for the Rcl column.
f. Enter the formula for the particle diameter (D) column.
Submittal Instructions:
Click here to upload your homework assignment.