The pH is the logarithm of the reciprocal of the molar concentration of the hydrogen ion and the pOH is the hydroxide ion. Take the two blue covers and repeat the above. Cut acrylic glass 17.5 x 21cm of red, orange, yellow, green, clear, and blue for a pH chart. Demonstrate how to use the mathemathical approach for signed numbers using the tube. Let red represent positive numbers and blue represent negative numbers.
Students can select a color from the pH range to represent the continuum of signed numbers.