Most people use cabbage for ... of minutes until the water turns a dark blue. This blue liquid is your indicator solution for the chemistry experiment. Next, pour about 1 tablespoon of the indicator ...

While holding the bag, squeeze the mixture of water and cabbage leaves until the water turns ... an empty, clear plastic cup, leaving the cabbage pieces behind in the bag. The liquid is your indicator ...

Other varieties of cabbage will not work. Mash up the red cabbage so the water you have added really does turn very purple. The more concentrated, the more noticeable the colour change.