Preparatory Work

The group decided

to have a go at extracting

the colour from a range

of different natural

materials:

• Cranberry,

• raspberry,

• saffron,

• red cabbage,

• blueberry,

• red onion skins

• ordinary onion skins,

• beetroot.

were each divided into

three equal portions in

test tubes.

Acid was added to one

test tube, alkali to

another, and the

colours compared to

the control.

These initial results

were used to select

which substances to

use in the

investigation.

and cranberries were difficult

to obtain after Christmas, so the

remaining substances

were selected.