Making an Indicator

at home

Boiling of the cabbage leaves for ten minutes.
Cut some red cabbage leaves and place the pieces in a small pot. Fill the pot with water and bring to boil. Boil for ten minutes. The red cabbage dye will slowly come out into the water and the leaves will turn a whitish colour.
Decant the purple coloured water into a cup. Take care not to spill any on your clothing or furniture as it will stain.
What you now have is a natural indicator. This indicator will change colour to identify acids or basic solutions.
Decant the dye into a cup.


Using small portions of the indicator do the following
Test you indicator using vinegar (a known acid).
Next test the indicator with detergents (a known base).
Notice and record the colour changes.

Identify a number of items in the kitchen as acids or bases. Make a table.

When acids are mixed with the water a distinct colour change occurs.Click to see a 120kb movie of the colour change that occurs when an acid is added to the indicator.