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Carminic acid provides a podcast or transcript about the widespread use and applications of the red dye we now know as cochineal, carminic acid or carmine.  The colour is pH dependent allowing the colour of a dye bath to be altered by adjusting the pH. Interesting insights are provided into popular opinions on a natural dye when it comes from bugs!

Chemical Tornadoes provides an eye-catching demonstration using indicators, together with suggestions for extending its application.

Rainbow Fizz. This popular and visually appealling demonstration of acid base indicators is revisited in this article and video with ideas for extending it for older students and relating the 'how to choose a suitable indicator' concept.

pH and indicators using a Comboplate

This CLEAPSS activity is another possible method to compare a range of indicators.