Prepared by: Christopher Nalaunan
Can Water Harness Be Determined through Soap Bubbles?
To see i f it is possible to estimate the hardness of a variety of waters from various wells and public water supply sources
solely by their bubble activity after being mixed with soap and s haken. .
Can water hardness be determined through soap bubbles?
We think that if we will test the amount of bubbles produced when a mixture of a water sample and soap is
shaken then we can determine the hardness of water.
*Amount of water
*Amount of soap
*Amount of Calcium Chloride
*Amount of bubbles
•5 1-liter containers
•5 liters distilled water
•Calcium Chloride (Magnesium chloride can besubstituted)
•Test tubes ( one for each benchmark solution andone for each water sample tested)
•Liquid hand soap
•Stoppers for the test tubes
•Black marking pen
•Test tube racks
•Tap water from various locations that could include either a well or a public water supply
•Hard water test kit (drop titration kit)
1) Prepare 1 liter of each of the hard and soft water benchmark solutions. The benchmark solutions
will be of 5 different grades of distilled water containing the calcium chloride-a soft water
solution (containing 0-17.1 mg/L), a slightly hardwater solution (17.1-60 mg/L),amoderately hard
water solution(60-120mg/L), a hard water solution(120-180mg/L), and a very hard water solution
2) Pour each solution into a separate test tube, filling it 1/3 of the way up.
3) Drop 1 drop of liquid hand soap into each test tube with the pipette. Cap the tubes with the
stoppers and shakevigorously for 10 seconds each. Then usea black marking pen to indicate
the highest point on the test tube that the bubbles reached. These will become your benchmark
samples. Place them in a test tube rack.
4. Take the first sample of tap water to be tested and pour 1/3 of the way up in a test tube. Drop 1 drop of liquid
handsoap into the test tube and shake vigorously for 10 seconds. Then, with the black marking pen,
indicate the highest point on the test tube that the bubbles reached. Repeat this step for each water
5. Once all your water samples are tested, compare the amount of bubbles generated in each sample
test tube with those of the benchmark test tubes and match the sample results with similar results
obtained from the benchmark group. Record your observations. For example, if one water sample
produced the same amount of bubbles as a benchmark tube that contains minerals that are
between 120-180mg/L, then record this observation with your estimate that the water in your
sample is probably hard.
6. Once you have compared all of your water samples, perform the actual hard water test on each
sample with the test kit. There are various test kits on the market for this procedure. Probably,
the easiest one to use is a drop titration kit.Follow the directions for testing hard water...