Foul Water Lab
Name ____________________________________
Period ____________ Date ___________________
Introduction
The purpose of this activity is to purify a sample of “foul” water, producing as much
“clean” water as possible. Do not test the purity of the water by drinking it.
Three water purification procedures will be used: (1) oil-water separation, (2) sand
filtration, and (3) charcoal adsorption/filtration. (Filtration is a general term for separating solid
particles from a liquid by passing the mixture through a material that retains the solid particles.
The liquid collected after filtration is called the filtrate.)
Procedure
1. Measure 100 mL of foul water with your graduated cylinder.
2. Examine the properties of your sample: color, odor, clarity, presence of solids on oily
regions. Record your observations in the “Before treatment” section of your data table.
Oil and Water Separation
1. Place the funnel with the attached rubber tubing in the funnel clamp.
2. Close the rubber tubing by using the pinch clamp. Shake or stir the foul water sample.
Then pour half the sample in the funnel and let it stand for a few seconds until the two
layers separate.
3. Carefully open the tube to release the lower layers into a 150-mL beaker. When the
lower layer has drained out, quickly close the rubber tube.
4. Drain the remaining layer into a second 150-mL beaker.
5. Repeat steps 2-4 using the remainder of the sample, adding each liquid in the correct
beaker.
6. Dispose of the top, oily layer as instructed by the teacher. Observe the properties of the
remaining layer and measure its volume. Record your observations and data. Save the
water sample for the next procedure.
7. Wash the funnel with soap and water.
Sand Filtration
1. In foam cup with small whole at the bottom, place a premoistened layer of gravel and sand as shown in the picture.
(The bottom gravel prevents the sand from washing
through the holes. The top gravel keeps the sand from
churning up when the sample is poured in.)
2. Gently pour the sample to be filtered into the cup. Catch the filtrate (filtered water) in a
beaker as it drains through.
3. Dispose of the used sand and gravel according to your teacher’s directions. Do not pour
sand or gravel into the sink!
4. Observe the properties and measure the volume of the water. Record your results. Save
the water sample for the next procedure.
Charcoal Adsorption/Filtration
1. Fold a piece of filter paper as seen in the picture.
2. Place the folder filter paper in the funnel. Wet the paper slightly so it adheres to the
funnel cone.
3. Place the funnel in the funnel clamp. Lower the ring clamp so the funnel extends 2-3 cm
inside a 150 mL beaker.
4. Place a small amount of charcoal into the funnel and pour the water sample slowly into
the funnel.
5. If the filtrate is darkened by small charcoal particles, refilter the liquid. Use a clean piece
of moistened filter paper.
6. When you are satisfied with the appearance and odor of your purified water sample, pour
it into a graduated cylinder. Observe and record the properties and the final volume of
the sample.
7. Return your purified water sample to your teacher.
8. Wash your hands thoroughly before leaving the laboratory.
Foul Water
Data and Questions
Name ____________________________________
Date ____________________ Period __________
Data Table
Color
Clarity
Odor
Presence
of Oil
Presence
of Solid
Volume
Before treatment
After oil-water
separation
After charcoal
adsorption/filtration
Questions
1. Using the classification of matter presented in class, classify your initial sample of foul
water.
2. What percent of the initial foul-water sample did you recover as “pure” water?
Vol. water purified
Vol. of foul water sample
x
100% = percent of water purified
____________________
x
100% =
% water purified
3. What volume of liquid did you lose during purification?
4. What percent of your initial foul-water sample was lost during purification?
5. During distillation, why did your teacher discard the first portion of the distillate?
6. Your teacher tested the electricity conductivity of your purified water sample. This test
checks for the presence of dissolved, electrically-charged particles in the water. Record
the results below.
Sample
Purified water sample
Electricity Conductivity
Tap water
Distilled water
What do these tests suggest about the purity of your water sample?
7. Distillation is not used by municipal water treatment plants. Explain.