Understanding the basics
pH is one of those words or terms
that you are familiar with and hear all over the place,
but sometimes arenít quite sure what it really means.
You will hear people talking about the pH of
swimming pools, garden soil, skin, chemicals and foods
amongst other things.
What does pH mean?
pH is a measure of how acidic or otherwise a solution or
substance is. We use a pH scale of 0 to 14 to assess the
acidity of various substances.
Pure water is the
standard to set the pH scale and has the value of 7.
This is known as neutral.
Acidic substances have
pH levels below 7 and basic (non acid) substances have
pHs greater than 7.
Variations in pH affect
animals, plants and inanimate objects.
instance, at pH 7.5, avocado, corn and mushrooms grow
very well but cauliflower, celery and lettuce may not
survive. Bilberries and cranberries, on the other hand,
like Ph of 4.5.
Swimming pools will ideally have
a pH of 7.4 to 7.6. High pH levels in a pool leads to
scale formation on the walls, cloudy water and
inefficient filter operation whilst low pH leads to
metal fittings rusting and stained plaster. Both high
and low pH will cause skin and eye irritation for
Small variations in pH can have a large
effect on the use of a substance. Changing the soil pH
of a hydrangea plant will change the flower colour from
pink to blue, and changing blood pH out of the normal
range (7.3 to 7.52 ) can be life threatening.
Strong acids and bases (such as anything with a pH of 1
or 13) can be very dangerous and reactive.
Unlike many other terms, pH isnít actually
an abbreviation; it really refers to the hydrogen ion
Water is made up of hydrogen and
oxygen. At normal temperatures, pure water will break
down into some single hydrogen atoms.
that has a much greater number of free hydrogen atoms is
known as an acid; fewer hydrogen atoms are found in
pH is calculated as the by
the formula pH = log10 1/[H+]
Due to the nature
of log equations, increasing the number of hydrogen
atoms actually decreases the pH. So, an acid has many
hydrogen atoms and a low pH. Compared to a base with few
hydrogen atoms and a high pH.
How do you measure
There are a number of tests available for
determining the pH of substances. The simplest test is
using litmus (or pH) paper which changes colour when
exposed to different pH levels.
are used for liquids and solids, and they may show
different colour results, but they are based on the
principle of testing how many hydrogen atoms are
In simple terms, if a test shows the
substance to be too acidic for your needs than adding a
base will neutralise it. Or if the test shows a basic
result, adding acid will lower the pH.
be taken when adjusting pH levels as the chemicals used
to do so can be dangerous and it is easy to over do it
and cause the opposite problem.
has a science degree and experience in writing technical
information in plain English to be easily understood. All technical and business writing needs are
met by www.wordconstructions.com.au