German version
Supermarket products:
| hybiscus tea
| baking powder, ingredients: acidic agent (diphosphate), leavening agent, sodium bicarbonate,
wheat starch
| natron
| baking soda | |
Glass wares:
| 4 gas collecting cylinder h = 20 cm, d = 4 cm
| 3 snap-cap vials 20 mL
| 3 glass stirring rods | |
Experimental procedure:
Four gas collecting cylinders are filled with a cold tea extract.
The extract in the first cylinder serves as reference solution. The other samples are mixed with leavening agents while stirring:
baking powder is added to the cylinder 2
natron is added to the cylinder 3
and baking soda is added to the cylinder 4.
Results:
The extract in cylinder 2 turns purple. The extract in cylinder 3 and 4 turns grey and green (brown) respectively.
Video clip (Download RealPlayer .rm file)The swollen red calyces of Hibiscus sabdariffa (often referred to as the hibiscus flower itself) which form the outer covering of the flower buds are dried and used to make a rosy citrus flavored tea. Hibiscus sabdariffa is a member of the Malvaceae family. The water soluble anthocyanins malvin (malvidin-3,5-glucoside) und myrtillin (different delphinidin 3-glucosides) belong to the ingredients of Malvaceae.
