AIM: To determine the factor that controls the rate of sediment deposition in quiet water.
PROCEDURE A
1.
2.
3.
4.
PROCEDURE B
5.
6.
1.
2.
PROCEDURE C
PROCEDURE D
3.
4.
Set up a plastic column on a ring stand using the tube clamps.
Be sure that the bottom cap is on tightly. Fill the tube ¾ full of water.
Obtain from your instructor a variety of sediments sizes of the same material
Beginning with the largest sized sediment, measure the average diameter in millimeters. Determine
the settling time by dropping a pinch of the sediment into the tube. Start the stopwatch when the
particle first hits the water and stop it when it first reached the bottom. Record the average
diameter and settling time on your Report Sheet.
Repeat Procedure 4 for all of the different sediment size.
Construct a line graph of these data.
Obtain from your instructor sediments of same sizes and shape but of different densities
Beginning with the highest density sediment. Determine the settling time by dropping a pinch of the
sediment into the tube. Record the average diameter and settling time on your Report Sheet.
Repeat Procedure 2 for all of the different sediment size.
Construct a line bar of these data.
1.
2.
Obtain from your instructor sediments of same volume and density but of different shapes
Beginning with the highest density sediment. Determine the settling time by dropping a pinch of the
sediment into the tube. Record the average diameter and settling time on your Report Sheet.
1.
2.
Observe the pattern of vertical deposition of the mixed sediments
On the diagram of a plastic tube, draw what you observed
DATA AND GRAPHS
Procedure A
Grain size
Settling Time
6-8mm
1.70seconds
4-6mm
2.06seconds
1-3mm
2.50seconds
Graph A
1.00%
0.80%
0.60%
0.40%
0.20%
0.00%
6-8mm
4-6mm
1-3mm
Procedure B
Density
Settling time
8.5g/cc
.50seconds
1.8g/cc
6.90seconds
1.13g/cc
7.5seconds
Graph B
Density(g/cc)
1.13
1.8
8.5
0
1
2
3
4
5
6
7
8
settling time (seconds)
settlinf time (seconds)
Shape
round
cylinder
flat
Procedure C
Settling time (sec)
2.0
3.11
4.65
GraphC
5
4
3
2
1
0
round
flat
cylinder
shape
DISCUSSION QUESTION
1. How does each of the following affect the time in which particles settle in quiet water when other
factors are equal?
a. Size: the bigger the particle the faster it falls
b. Density: The more dense a particle is the faster it falls
c. Shape: The rounder the particle the faster the particle falls
2. What size particles seem to stay suspended indefinitely in a quiet body of water?
Extremely small particles
3. What is your description of the appearance of material which accumulates on the bottom of the
tube following the addition of a mixed sample of sediments to quiet waters?
Small rocks that are piled on top of one another
4. Besides the properties of the particle itself, what other factors can affect the settling rates?
Angel in which the particle falls into the quiet water