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How to Do Experiments With the pH Scale

A potential hydrogen (pH) scale measure how the acidic or base levels in a solution. This is important because different living organisms thrive in different pH levels. Knowing how to measure pH scale allows us to foster environments that are advantageous to the life forms we choose. For instance, aquariums require the right pH for pet fish to live. Swimming pools also require the right pH level to prevent fungus and bacteria from growing, while still being a safe environment for humans. Simple experiments with pH scale can show you just what different pH levels mean.

Things You'll Need

Test tubes and racks
Marking pen
Measuring cylinders
Dropper
Hydrochloric acid solution
Distilled water
Sodium hydroxide solution
pH indicator
pH indicator chart

Instructions

- 1
  Number the test tubes 1 through 13. Set aside numbers 8 through 13 for a later step.
- 2
  Fill the first test tube half-full with hydrochloric acid solution. Pour 1 centimeter of the hydrochloric acid into a measuring cylinder. Add enough distilled water to measure 10 centimeters in the cylinder.
- 3
  Pour the mixture from the measuring cylinder into the second test tube. Add enough to equal the amount in the first test tube.
- 4
  Discard all but one centimeter of the mixture in the measuring cylinder. Add distilled water to measure 10 centimeters. Pour the solution into the third test tube to measure the same amount as in the first and second test tubes.
- 5
  Continue to discard all but one centimeter in the measuring cylinder and adding distilled water to 10 centimeters. You will continue this step to fill test tubes 4, 5, 6. Test tube 7 will be filled with only distilled water.
- 6
  Repeat the above steps to fill test tubes 8 through 13, substituting sodium hydroxide solution instead of the hydrochloric acid.
- 7
  Place the 13 test tubes in order from 1 to 13 in the test tube racks. These test tubes represent the pH scale from pH 1 to pH 13.
- 8
  Place 1 drop of a pH indicator to each of the 13 test tubes. Gently swirl the solution in the tube to mix. A pH indicator is a substance that creates one color for acidic solutions and a different color for alkaline solutions.
- 9
  Compare the colors of the test tubes to the pH indicator chart. If the colors are not visible enough, you may add additional drops of pH indicator so long as the same amount of drops is used in each test tube.

Nature