Water+Standards+at+Taipei+American+School

Environmental Health & Safety (at TAS)

 // Topic: // Water Safety Experimenters: Andrew, Azri, Vickie, Jacci, Melody  __Research Question:__ What are differences in pH level, calcium, and chlorine in varying water sources at TAS? __Underlying Question:__ Which water sources are safe for drinking?

**Aim:** To observe and evaluate the different water qualities in TAS through measurements of pH, mineral, and chlorine levels to determine which water sources are safe for drinking.


 * __ Condition __ || Explanation ||
 * __ Independent Variable: __ Different types of water (Pool Water, Drinking Fountain Water, Tap Water, Water Dispenser water) || Four primary water sources found in Taipei American School are selected to measure and compare the pH, amount of Chlorine and Calcium in the solutions. ||
 * __ Dependent Variable: __ Levels of pH, Amount of chlorine, magnesium, calcium || The tested factors were selected to ensure that the water is safe for drinking in drinking water, and that the water is safe for the human body in swimming water. ||
 * __ Control Group __: Deionized water || Theoretically deionized water should not contain high traces of chemicals. Therefore it is used as the control group for the experiment. ||
 * __ Control Variable: __ Quantity of Water || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">The quantity of the water used in the actual experiment should be kept constant. Particularly in the experiment measuring for calcium and chlorine. ||
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">__ Control Variable: __ Temperature of Solution || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">Because temperature is not the independent variable, it should be kept constant throughout the experiment. For this lab, the experiment will be conducted in room temperature of approximately 23 degrees Celsius. ||
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">__ Control Variable: __ Light Intensity || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">Light intensity is also not a factor measured in the experiment. To ensure that the light intensity remain constant, conduct the experiment in the same location with the same light source. ||
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">__ Control Variable: __ Consistency in Equipment || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">The equipment used for measurement should be consistent throughout the experiment. For example when measuring for pH, if possible use the same pH probe to ensure the most accurate data. ||


 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">Material || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">Quantity ||
 * <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">400mL Beaker || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 110%; text-align: left;"> Five ﻿﻿﻿ ||
 * <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">100mL Beaker || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Five ||
 * <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Temperature Probe || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Five ||
 * <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">pH Probe || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">One ||
 * <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Computer with Loggerpro || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">One ||
 * <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">pH Calibrating solution || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">20mL ||
 * <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Measuring Cylinder || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Two ||
 * <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Pipette || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Four ||
 * <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Pool water, drinking fountain water, tap water, water dispenser water, deionized water || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">500mL each ||
 * <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">soap || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">20mL ||
 * <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Nitric acid solution || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">10mL ||
 * <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Silver nitrate solution || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">10mL ||
 * <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">50 mL Test tube || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Six ||
 * <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Stop watch || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">One ||
 * <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Parafilm || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">30cm ||
 * <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Scissors || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">One ||
 * <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Test tube rack || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">One ||
 * <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">A4 size black paper || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">One ||
 * <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Tape || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">One roll ||
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;"> Filtration Tube || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;"> One ||
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;"> Large Test Tube (100ml) || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;"> One ||

<span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;"> ** Procedure: **

<span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Preparatory Stage: <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">1) Collect water samples from different conditions <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">2) Pour samples into 400mL beakers and label beakers accordingly

<span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Measuring pH: <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">3) Using a measuring cylinder, pour 50mL of pool water into a 100mL beaker <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">4) Set up Loggerpro and calibrate one pH probe <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">5) Measure pH of pool water <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">6) Repeat steps 3-5 five times <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">7) Repeat steps 3-6 for deionized water, fountain water, tap water, and water dispenser water

<span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Measuring Magnesium and Calcium: <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">8) Using a measuring cylinder, pour 20mL of pool water into a 50mL measuring cylinder <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">9) Pour 1mL of soap into the cylinder <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">10) Seal the opening with parafilm and swirl the cylinder in circular motion for one minute <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">11) Remove the plastic wrap and measure the height of bubbles <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">12) Repeat steps 8-11 five times <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">13) Repeat steps 8-12 for deionized water, fountain water, tap water, and water dispenser water

<span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">Measuring for Chlorine: <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">14) Prepare diluted (5%) nitric acid solution <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">15) Prepare Silver nitrate test solution (dissolve 1.7 grams of silver nitrate crystals into 98 ml of distilled water. Store in dark background) <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">16) Place 20ml of pool water into a clean test tube <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">17) Add two drops of diluted nitric acid. <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">18) Shake the solution to mix. If the solution fizzes, continue to add acid until the fizz stops. <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">19) Hold up test tube to strong light source on one side with a dark side behind the test tube. Add two drops of Silver nitrate test solution. <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">20) Observe sample and record data. <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">21) Repeat steps 14-20 five times <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">22) Repeat steps 14-21 for deionized water, fountain water, tap water, and water dispenser water

<span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">**__Table 1: pH Levels of Varying Water Sources (Measured using a pH probe)__**
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">Be sure to calibrate pH probe prior to experimentation
 * || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Trial 1 || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Trial 2 || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Trial 3 || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Trial 4 || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Trial 5 || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Mean || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">T-Test || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Standard Deviation || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">% of STDEV ||
 * <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Pool Water || <span style="color: black; display: block; font-family: 'Times New Roman',Times,serif; font-size: 110%;">6.30 || <span style="color: black; display: block; font-family: 'Times New Roman',Times,serif; font-size: 110%;">6.52 || <span style="color: black; display: block; font-family: 'Times New Roman',Times,serif; font-size: 110%;">6.74 || <span style="color: black; display: block; font-family: 'Times New Roman',Times,serif; font-size: 110%;">6.94 || <span style="color: black; display: block; font-family: 'Times New Roman',Times,serif; font-size: 110%;">5.81 || <span style="color: black; display: block; font-family: 'Times New Roman',Times,serif; font-size: 110%;">6.46 || <span style="color: black; display: block; font-family: 'Times New Roman',Times,serif; font-size: 110%;">0.00 || <span style="color: black; display: block; font-family: 'Times New Roman',Times,serif; font-size: 110%;">0.44 || <span style="color: black; display: block; font-family: 'Times New Roman',Times,serif; font-size: 110%;">7% ||
 * <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Deionized Water (Control) || <span style="color: black; display: block; font-family: 'Times New Roman',Times,serif; font-size: 110%;">7.50 || <span style="color: black; display: block; font-family: 'Times New Roman',Times,serif; font-size: 110%;">7.11 || <span style="color: black; display: block; font-family: 'Times New Roman',Times,serif; font-size: 110%;">7.45 || <span style="color: black; display: block; font-family: 'Times New Roman',Times,serif; font-size: 110%;">7.32 || <span style="color: black; display: block; font-family: 'Times New Roman',Times,serif; font-size: 110%;">7.12 || <span style="color: black; display: block; font-family: 'Times New Roman',Times,serif; font-size: 110%;">7.30 || <span style="color: black; display: block; font-family: 'Times New Roman',Times,serif; font-size: 110%;">1.00 || <span style="color: black; display: block; font-family: 'Times New Roman',Times,serif; font-size: 110%;">0.18 || <span style="color: black; display: block; font-family: 'Times New Roman',Times,serif; font-size: 110%;">2% ||
 * <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Water Dispenser || <span style="color: black; display: block; font-family: 'Times New Roman',Times,serif; font-size: 110%;">7.22 || <span style="color: black; display: block; font-family: 'Times New Roman',Times,serif; font-size: 110%;">7.96 || <span style="color: black; display: block; font-family: 'Times New Roman',Times,serif; font-size: 110%;">7.63 || <span style="color: black; display: block; font-family: 'Times New Roman',Times,serif; font-size: 110%;">7.64 || <span style="color: black; display: block; font-family: 'Times New Roman',Times,serif; font-size: 110%;">7.49 || <span style="color: black; display: block; font-family: 'Times New Roman',Times,serif; font-size: 110%;">7.59 || <span style="color: black; display: block; font-family: 'Times New Roman',Times,serif; font-size: 110%;">0.08 || <span style="color: black; display: block; font-family: 'Times New Roman',Times,serif; font-size: 110%;">0.27 || <span style="color: black; display: block; font-family: 'Times New Roman',Times,serif; font-size: 110%;">4% ||
 * <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Tap Water || <span style="color: black; display: block; font-family: 'Times New Roman',Times,serif; font-size: 110%;">6.60 || <span style="color: black; display: block; font-family: 'Times New Roman',Times,serif; font-size: 110%;">6.20 || <span style="color: black; display: block; font-family: 'Times New Roman',Times,serif; font-size: 110%;">6.18 || <span style="color: black; display: block; font-family: 'Times New Roman',Times,serif; font-size: 110%;">6.27 || <span style="color: black; display: block; font-family: 'Times New Roman',Times,serif; font-size: 110%;">5.88 || <span style="color: black; display: block; font-family: 'Times New Roman',Times,serif; font-size: 110%;">6.23 || <span style="color: black; display: block; font-family: 'Times New Roman',Times,serif; font-size: 110%;">0.00 || <span style="color: black; display: block; font-family: 'Times New Roman',Times,serif; font-size: 110%;">0.26 || <span style="color: black; display: block; font-family: 'Times New Roman',Times,serif; font-size: 110%;">4% ||
 * <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Water Fountain || <span style="color: black; display: block; font-family: 'Times New Roman',Times,serif; font-size: 110%;">6.35 || <span style="color: black; display: block; font-family: 'Times New Roman',Times,serif; font-size: 110%;">5.81 || <span style="color: black; display: block; font-family: 'Times New Roman',Times,serif; font-size: 110%;">6.11 || <span style="color: black; display: block; font-family: 'Times New Roman',Times,serif; font-size: 110%;">6.26 || <span style="color: black; display: block; font-family: 'Times New Roman',Times,serif; font-size: 110%;">6.18 || <span style="color: black; display: block; font-family: 'Times New Roman',Times,serif; font-size: 110%;">6.14 || <span style="color: black; display: block; font-family: 'Times New Roman',Times,serif; font-size: 110%;">0.00 || <span style="color: black; display: block; font-family: 'Times New Roman',Times,serif; font-size: 110%;">0.21 || <span style="color: black; display: block; font-family: 'Times New Roman',Times,serif; font-size: 110%;">3% ||

<span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">**__Graph 1:__** **__pH Levels of Varying Water Sources (Measured using a pH probe)__**
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">Be sure to calibrate pH probe prior to experimentation
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">Error bars reflect the standard deviation (shown in Table 1)

<span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">

<span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">__**Results and Explanations:**__

<span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">The data reveals certain trends of pH levels in the different water sources. In pool water, the pH level was generally around 6.00, and the mean was 6.46. This indicates that the pH level in pool water is slightly more acidic than the optimum pH level of 7. In deionized water, the pH level was around 7, with a mean of 7.3, thus indicating that the pH level of the deionized water is at its optimum level. In the water dispenser water, the mean of the pH levels gathered from all 5 trials was 7.58 which means that the pH level of the water dispenser water is slightly more basic than the optimum level for pH. The mean pH level of tap water was 6.2 which is slightly more acidic than the optimum pH level. Lastly, the mean of the pH level in the water fountain was 6.14 which is also slightly more acidic than the optimum pH level. From these results, one can deduce that pH levels in deionized water was close to the optimum pH level compared to water from the other sources. The pH in pool water, tap water, and the water fountain was found to be more acidic than usual, while the pH in the water dispenser water was more basic. This could be attributed to the unequal balance of hydrogen and hydroxide ions within the different water sources which resulted in a variation of pH levels.


 * ===<span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">**Procedure and Method** === || ===<span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">**Evaluation of the Procedure or Method** === || ===<span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">**Suggestions for Improvement** === ||
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">Range of independent variable || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">The source of water is the independent variable tested. The five sources selected were an appropriate representation of the sources of water available at the campus of TAS. || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">To improve the experiment the sources of water could be expanded to include sewage water and bottled water for a more comprehensive report. ||
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">pH was measured with pH probes || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">The pH of the solution could change with exposure to light and carbon dioxide. || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">In the future for more accurate results, light exposure should be minimized (conduct the experiment in minimal light setting). ||
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">5 trials were completed at each temperature || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">Having five trials allow for relatively accurate results. Five trials allow the experimenter to observe trends in results and identify outliers in the set of data. || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">To make the results more accurate, more trials could be completed to further increase the accuracy of the results. ||
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">Equipment || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">**__pH Probes:__** pH probes accurately measure the pH level. However the accuracy of the pH probe could depend on the condition of the probes.

<span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">Because of the precision of the tools and human errors, the accuracy of the results may have been compromised. || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">**__pH Probes:__** In the future be sure to calibrate the pH probes prior to experimentation to the higher degree of accuracy. ||

<span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">**__Table 2:__** **__Calcium in Varying Water Sources (Measured through height of bubbles)__** <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">Data Result <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">ddH2O + Ca(NO3)2 || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">6.3 || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">6.1 || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">5.7 || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">6.0 ||
 * || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">Trial 1 (cm) || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">Trial 2 (cm) || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">Trial 3 (cm) || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">Average (cm) ||
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">Pool Water || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">6.5 || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">7 || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">6.9 || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">6.8 ||
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">Deionized Water || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">12.5 || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">12.12 || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">12.8 || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">12.5 ||
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">Water Dispenser || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">9.5 || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">9.7 || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">9.3 || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">9.5 ||
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">Tap Water || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">9 || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">8.8 || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">9.2 || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">9.0 ||
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">Water Fountain || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">8.5 || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">8.9 || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">8.7 || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">8.7 ||
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">Hardened Water (200mg/l)

<span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">Calculation <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">e.g. Pool Water <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">12.5 cm bubbles/1 cm3 = 6.8 cm/x cm3 soap <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">X = volume of soap needed to create 12.5 cm of bubbles

<span style="background-color: transparent; color: #000000; font-family: 'Times New Roman',Times,serif; font-size: 110%; text-decoration: none; vertical-align: baseline;">**Conclusion:** The control group used to measure an appropriate level of bubbles was the the deionized water, as it could be assumed that no calcium ions were present. The calcium present reacted with the ethylene glycol monostearate in the soap to prevent the formation of bubbles. Originally, the setup of the lab measured the total height of bubble formation with a constant amount of soap added to each sample of water (1 ml). However, using the height of bubble formation in deionized water, ratios could be derived to discover the corresponding amount of soap needed to create the same height of bubbles for the other compounds. The less soap necessary for forming a bubble height of 12.5 cm, the harder the water (higher concentration of calcium present). The manipulated data indicates that the pool water had the highest calcium concentration, followed by the tap water and fountain water (equal amounts of soap necessary), the water from the dispenser, and finally the deionized water. Even though the hardness of water is not directly detrimental to the health of an individual, it can cause the breakdown of equipment.
 * || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">Average (cm) || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">X (cm) ||
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">Pool Water || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">6.8 || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">0.5 ||
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">Deionized Water || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">12.5 || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">1.0 ||
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">Water Dispenser || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">9.5 || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">0.8 ||
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">Tap Water || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">9.0 || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">0.7 ||
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">Water Fountain || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">8.7 || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">0.7 ||
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">Hardened Water (200mg/l) ddH2O + Ca(NO3)2 || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">6.0 || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">0.5 ||

<span style="background-color: transparent; color: #000000; font-family: 'Times New Roman',Times,serif; font-size: 110%; text-decoration: none; vertical-align: baseline;">1. Keeping a constant force when shaking the solution, which determines the height of the bubbles. <span style="background-color: transparent; color: #000000; font-family: 'Times New Roman',Times,serif; font-size: 110%; text-decoration: none; vertical-align: baseline;">2. The errors of reading the bubbles height; bubbles consist of air in between, which made it hard to make an accurate measurement of the height
 * <span style="background-color: transparent; color: #000000; font-family: 'Times New Roman',Times,serif; font-size: 110%; text-decoration: none; vertical-align: baseline;">Possible sources of error: **

<span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">**__Table 3: Level of Chlorine in Varying Water Sources (Higher precipitation reflects higher chlorine concentration)__** <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">High Precipitation || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;"> ||
 * || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Trial 1 || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Trial 2 || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Trial 3 || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Trial 4 || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Trial 5 || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Mean ||
 * <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Pool Water || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">High Precipitation || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">High Precipitation || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">High Precipitation || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">High Precipitation || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">High Precipitation || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">[[image:pool.jpg width="105" height="126"]]
 * <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Deionized Water (Control) || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">No Precipitation || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">No Precipitation || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">No Precipitation || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">No Precipitation || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">No Precipitation || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">No Precipitation
 * <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Water Dispenser || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Low Precipitation || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">No Precipitation || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">No Precipitation || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">No Precipitation || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">No Precipitation || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">[[image:water_dispenser.jpg width="101" height="164"]] No Precipitation ||
 * <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Tap Water || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Medium Precipitation || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Medium Precipitation || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Medium || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Medium Precipitation || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Medium Precipitation || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">[[image:tap.jpg width="104" height="152"]] Medium Precipitation ||
 * <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Water Fountain || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Low Precipitation || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Low Precipitation || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Low Precipitation || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Low Precipitation || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Low Precipitation || <span style="color: black; font-family: 'Times New Roman',Times,serif; font-size: 110%;">[[image:Water_Fountain.jpg width="110" height="185"]]Low Precipitation ||


 * <span style="background-color: transparent; color: #000000; font-family: 'Times New Roman',Times,serif; font-size: 110%; text-decoration: none; vertical-align: baseline;">Description of Results || <span style="background-color: transparent; color: #000000; font-family: 'Times New Roman',Times,serif; font-size: 110%; text-decoration: none; vertical-align: baseline;">Significance/ Explanation of Results ||
 * <span style="background-color: #d3dfee; color: #000000; font-family: 'Times New Roman',Times,serif; font-size: 110%; text-decoration: none; vertical-align: baseline;">Pool water illustrated high signs of precipitation || <span style="background-color: #d3dfee; color: #000000; font-family: 'Times New Roman',Times,serif; font-size: 110%; text-decoration: none; vertical-align: baseline;">- Since pool water uses chlorine as a disinfectant, it is obvious that it will show high signs of precipitation after silver nitrate solution and nitric acid solution, which are used to detect chloride, are added. Precipitation is created through is the reaction of the contact of chloride, silver nitrate, and nitric acid. ||
 * <span style="background-color: transparent; color: #000000; font-family: 'Times New Roman',Times,serif; font-size: 110%; text-decoration: none; vertical-align: baseline;">Deionized water is the control variable. It showed no signs of precipitation || <span style="background-color: transparent; color: #000000; font-family: 'Times New Roman',Times,serif; font-size: 110%; text-decoration: none; vertical-align: baseline;">- Since deionized water is a kind of water that is physically processed to remove any kinds of impurities, there won’t have any chloride in it, thus no precipitation. ||
 * <span style="background-color: #d3dfee; color: #000000; font-family: 'Times New Roman',Times,serif; font-size: 110%; text-decoration: none; vertical-align: baseline;">Water dispenser water showed no signs of precipitation || <span style="background-color: #d3dfee; color: #000000; font-family: 'Times New Roman',Times,serif; font-size: 110%; text-decoration: none; vertical-align: baseline;">- Water dispenser water shows similar characteristics to deionized water, thus no precipitation. ||
 * <span style="background-color: transparent; color: #000000; font-family: 'Times New Roman',Times,serif; font-size: 110%; text-decoration: none; vertical-align: baseline;">Tap water showed medium precipitation || <span style="background-color: transparent; color: #000000; font-family: 'Times New Roman',Times,serif; font-size: 110%; text-decoration: none; vertical-align: baseline;">- Since tap water is only potable water, which is only water clean to a certain extent with fairly low risks of harm, it contains impurities such as chloride, thus precipitation. ||
 * <span style="background-color: #d3dfee; color: #000000; font-family: 'Times New Roman',Times,serif; font-size: 110%; text-decoration: none; vertical-align: baseline;">Water fountain water showed low precipitation || <span style="background-color: #d3dfee; color: #000000; font-family: 'Times New Roman',Times,serif; font-size: 110%; text-decoration: none; vertical-align: baseline;">- Water fountain water shows similar traits to tap water as it isn’t intended for long usage, it has some or little chloride, thus there is a low amount of precipitation. ||


 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">**Procedure and Method** || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">**Evaluation of the Procedure or Method** || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">**Suggestions for Improvement** ||
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">Prepare silver nitrate solution and set in the dark || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">Silver nitrate solution is light sensitive therefore light exposure must be kept to a minimum. || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">In the future, the experiment could be conducted in the dark to avoid exposure to light outside of actual experimentation ||
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">Add two drops of dilute nitric acid || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">The quantity of dilute nitric acid added to the water source is not specific enough. This could have resulted in different levels of precipitation. || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">Apparatus should be kept constant (use the same pipette throughout the entire experiment) ||
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">Shake the solution to mix || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">In the first part silver nitrate was added water to form the silver nitrate solution. The silver nitrate crystals could have set in the bottom of the beaker after some time. || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">Be sure to thoroughly mix the silver nitrate test solution before commencing the experiment ||
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">Five trials || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">Five trials allow for accurate results and standard deviation so that different results can be compared. || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">In the future for more accurate results, more trials could be completed. ||