Water Purity Lab
Zach Hand
Chemistry
Period A-B
Problem Definition:
Problem Statement:
Can the dirty water be made cleaner and more pure?
Hypothesis:
If the water is filtered through filter paper then any oils and solids will be drained out and
the water will become cleaner.
Variables:
The independent variable is what kind of filtration method is used and the dependent
variable is the amount of water filtered through each method.
Experimental Design:
1. Obtain 100mL of foul water using a beaker.
2.
Measure the volume of the sample with a graduated cylinder and record your
observations.
3.
Examine your sample. Record your observations in your data table.
4. Place a clay triangle on the ring of a ring stand.
5. Place a funnel through the clay triangle.
6. Attach a rubber tube to the funnel and use a metal clamp to pinch it closed.
7. Pour the sample into the funnel and let the liquid layers separate.
8. Slowly release the lower layer of water into a 150mL beaker.
9. Release the remaining water into another beaker.
10. Dispose of the oily layer and measure the volume of the remaining layer. Record
your results and save the sample.
11. Clean the funnel and tube.
Sand Filter
1. Poke holes in the bottom of a disposable cup using a straightened paper clip
2. Add pre-moistened gravel and sand layers to the cup
3. Pour the sample to be filtered into the cup. Catch the filtered water in a beaker as
it drains through.
4. Dispose of the used sand and gravel.
5. Observe the filtered sample. Record the results. Save the sample.
Charcoal Adsorption and Filtration
1. Place a folded piece of filter paper in the funnel.
2. Place the funnel in a clay triangle on the ring stand. Make the ring extend 2-3 cm
into the 150mL beaker.
3. Place one teaspoon of charcoal in a 125- or 250-mL Erlenmeyer flask.
4. Pour the sample into the flask and swirl it.
5. Pour the liquid through the filter paper.
6. If the water is dark with charcoal particles, refilter it through a clean piece of filter
paper.
7. Pour the filtered water into a graduated cylinder and record the final volume.
8. Dispose of the sample and used charcoal properly.
9. Wash your hands and clean up before leaving the laboratory
Results of Experiment:
Volume
Color
Clarity
Odor
(mL)
Before
100 mL
treatment
After Oil-
77 mL
water
Presence
Presence
of Oil
of Solids
Yes
Yes
Ugly
Very
Chinese
brown
murky
food
Dirty
Clearer
Greasy
No
Yes
Barely
Weak
No
Very little
clear
grease
No
No
Water
separation
After sand
56 mL
Tan color
filtration
smell
After
31 mL
Clear
Very clear
None
Charcoal
adsorption
and
filtration
Calculations:
Unable to be shown since data was not taken accurately
Questions:
1. Is your “purified water” sample “pure” water? How do you know?
A: No. There could still be particles or bacteria in the water.
2. Suggest how you might compare the quality of your water sample with that of
other laboratory groups. That is, how can the relative success of each laboratory
group be judged? Why?
A: You could test water purity and check how pure each group’s water is to compare
them.
3. How would you improve the water-purification procedures you followed so that a
higher percent of purified water can be recovered?
A: To make the water more pure, you could do multiple filtrations.
4. a. Estimate the total time you expended in purifying your water sample.
A: 1 Hour 9 Minutes
4. b. In your view, did that time investment result in a large enough sample of
sufficiently purified water?
A: No. There are better methods to purify water.
4. c. i. If you spent twice as much time in purifying your sample, would that extra
investment in time “pay off” in higher-quality water?
A: Yes, but there wouldn’t be a significant difference
4. c. ii. If you spent about ten times as much time?
A: There would be a significant difference because the water would have been
filtered so many times.
5. Municipal water-treatment plants do not use distillation to purify the water.
Why?
A: Because distillation takes too long and costs more than other types of filtration.
Conclusions From the Experiment:
The data doesn’t completely support the hypothesis. In some of the water samples there
was still oil or solids present after filtration. With more filtration, the solids or oils may
have been filtered out.
Validity and Reliability
The reliability of these results may not be accurate since the amount of water used for
each test may have been slightly different than was indicated. The amount of time for
filtration may have also differed for each sample. There were also possible spills at
times.