pH Scale Interactivity
This interactive lesson will allow you to see how acidic or basic common substances are.
You can also see what happens to the pH if you add more water (i.e. dilute the substance) -- you should notice that it becomes more neutral (the pH gets closer to 7) if you add water.
As you play with this interactive pH scale, you can see how many H3O+ (hydronium) and OH- (hydroxide) molecules are in each substance, by checking the boxes beneath the beaker labeled "molecule count" and "H3O+/OH- ratio". The more H3O+ (red) molecules there are, the more acidic the substance is. The more OH- (blue) molecules, the more basic the substance. The pH scale is logarithmic, which means each number on the pH scale represents a 10x increase in value. For example, pH 4 is ten times more acidic than pH 5 and 100 times (10 times 10) more acidic than pH 6. For pH values above 7, each is ten times more alkaline (or basic) than the next lower whole value. For example, pH 10 is ten times more alkaline than pH 9 and 100 times (10 times 10) more alkaline than pH 8.
Which items are acidic? Which items are basic? Scroll to the bottom of this page to see the answers!
PhET Interactive Simulations
University of Colorado
Last modified: Thursday, 15 September 2011, 9:53 AM