15. How do scientists measure the strength of an acid or a base? They use a pH scale. A pH scale measures the concetration of Hydronium ions ,H⁺, (an acid) or Hydroxide ions, OH⁻, (a base)
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18. Some plants prefer acidic soil with a pH between 4 and 6. Other plants need basic soil with a pH between 8 and 9.
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Editor's Notes
Acids are used in swimming pools to prevent algae growth.In mining acids are used to separate metals from the rock is embedded in. In many cases Sulfuric acid is used which is the same acid found in batteries.
Lime (a base) is used in cement to help it bind better.
Farmers and gardeners are concerned with the pH of their soil. Depending on the acidity or alkalinity of the soil farmers/gardeners will know which fertilizer will help their crops grow the best.
Hydrangeas need acid to produce this blue color. That’s why gardeners add coffee grounds, which is acidic to the soil around them.The colors on this hot spring pool are created by heat and acid loving bacteria.Acid rain is responsible for the difference in color of these evergreen branches as well as the death of the fishes in many lakes.Acid rain also affects the oceans changing the pH of the water, affects the delicate balance of sea life.