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Lab #2 Indicators- How is measurement of pH useful?
Materials: Test tubes, Substances, A, B and C red and blue litmus paper, oH paper with chart Bromothymol blue and straw.
Procedure:   Fill test tubes with 15 drops of substance A, place litmus blue and red, and PH paper in it, record the color change. Do the same for substance B and C. Then fill the last tube with water half way, and then add 5 drops of Bromothymol blue. Record initial color then place straw on the tip of the water and blow gently. Exhale until a color change then record all your data. WARNING: DO NOT MIX OR CONTAMINATE THE SUBSTANCES
  1. A: Initial- Red = Blue
    After Color Change- Blue = Blue
Ph. Level – 11 Basic
  2. B: Initial- Red = Pink
    After Color Change- Blue = Red
Ph. Level – 1 Acidic
  3. C: Initial- Red = Red
    After Color Change- Blue = Red
Ph. Level – 7 Neutral
-Bromothymol Blue
    Initial- Blue-green
    After color change- Lime Yellow
  4. Assume the color change is caused by acidity produced by the carbon dioxide in your breath. Test this hypothesis making use of what you have learned. Report your procedure and results.
-We made the liquid change by breathing through a straw when we did it, it started to change colors. You can test it by dropping a pH paper and determine to a color that is active.

  5. Use what you have learned to show that a fish breaths out carbon dioxide
-Pour out water from the fish tank and add Bromothymol blue, if it changes color to lime green then there is an existence of carbon dioxide.