Fun with flowers

Asian pigeonwings locally known as ‘Katarolu’ flowers are quite common in Sri Lanka. Here’s a fun experiment you can perform with these flowers;

MATERIALS

Asian pigeonwing flowers Mortar and pestle Small piece of cotton cloth Small container Freshly squeezed lemon White saucer

INSTRUCTIONS

Place a few Asian pigeonwings (10-20) in the mortar and grind the flowers with the pestle until a fine blue solution is obtained. (You may need to add a little bit of water as well).

Filter out the blue solution using the cotton cloth into a small container. (Filtering helps to obtain a consistent liquid and prevents uncrushed large pieces of petals from being collected).

Wring the cloth to squeeze out the remainder of the solution. Add a few drops of the blue flower solution on to a white saucer. Mix a drop of colourless lemon juice on to the blue drop on the white saucer. Watch what happens. The colour of the drop changes from blue to pink!

HOW IT WORKS

The juice obtained by crushing the flower petals is called a natural ph indicator. This helps determine whether a particular substance is acidic or not. The blue colour changes to pink if an acid is added. If the substance is not acidic there would be no colour change. Since lemon is acidic you were able to observe a colour change. What other substances would change the blue colour indicator to pink? Why not test out some other fruit samples and find out yourself? Happy experimenting!