 We will mix a solution of crystal violet with a solution of sodium hydroxide. We will swirl the solution so they mix. We will then fill the cuvette with the solution. As the reaction mixture stands, the sodium hydroxide and crystal violet react. The crystal violet undergoes a change and becomes colorless. We see the color fade with time. We will calibrate the 0% T with nothing in the colorimeter. We set the colorimeter to 0% T. We wait until the reading on the CBL stabilizes and then we press trigger on the CBL. We then enter 0 on the calculator and press enter. We now set the colorimeter to the green light emitting diode. We put into the colorimeter our blank solution containing the sodium hydroxide. We wait for the reading on the CBL to be stable again. Press trigger and enter 100%. This gives us slope and intercept. We press enter and it takes us back to the main menu. As the reaction mixture stands, the sodium hydroxide and crystal violet react. The crystal violet undergoes a change and becomes colorless. We see the color fade with time.