1. For this experiment you
will want to test your items to see
if they are an acid, an alkali or
2. All the items that you
are planning to test need to be made
up as a solution by adding just a
bit of water and mix so that the universal
indicator paper can absorb some of
3. Dip your universal indicator
paper into each item you are testing.
The paper will turn red if it is an
acid and blue if it is an alkali.
This paper has a mixture of dyes which
produces a range of colors which tell
us not only if a solution is an acid
or alkali but also how acidic or how
alkaline it is.
4. Record your findings
in a table. Have a column for ‘Food’,
Acid, Neutral and Alkali.
The pH numbered scale ranges
from 1 to 14.
- Solutions that are less
than 7 pH value are acidic and turn
the universal indicator paper red.
- Solutions that are above
7 pH value are alkaline and turn the
universal indicator paper blue.
- Solutions that are neutral
will read as 7 on the pH numbered
Did you know?:
your stomach contains hydrochloric
acid which helps to digest your
bite from an ant contains formic
acid. The acid from this bite is
what makes the bite itch or sting.
car battery contains a strong acid
called sulphuric acid.
fruits contain an acid called citric
contains another acid call acetic
acid or ethanoic acid.
~ If you are stung by a
bee you should rub an alkaline
solution like camomile or a baking
soda solution to help stop the
sting. A bee injects an acidic
solution that irritates the skin
so by rubbing the alkaline solution
this helps to balance out the
you are stung by a yellow jacket
you should rub an acid solution
like vinegar on the sting to help
with the pain. A yellow jacket
injects an alkaline solution that
irritates the skin so by rubbing
an acidic solution this helps
to balance out the cause.
~ Some acids are more dangerous
~ Acids and alkalis are
not all the same strength. Concentrated
solutions are the most dangerous.
Less dangerous acids:
~ Citric acid - lemonade
~ Ethanoic acid - vinegar
~ Tartaric acid - baking
More dangerous acids:
~ Hydrochloric acid - weak
solution in the stomach
~ Sulphuric acid - car batteries
~ Nitric acid - cleaning metals