TLF ID M015755
It might sound 'un-sciencey', and have a bad smell, but red cabbage is actually very useful for testing the pH of liquids. Added to well-known liquids like lemonade or vinegar, red cabbage juice changes to 'pretty colours'. In this clip, Surfing Scientist Ruben Meerman explains the colour changes and how red cabbage juice indicates if a liquid is an acid or a base.