Surface tension is a phenomenon in which the surface of a liquid, where the liquid is in contact with gas, acts like a thin elastic sheet. This term is typically used only when the liquid surface is in contact with gas (such as the air). Causes of Surface Tension.
There are several varieties commonly available, including White Vienna, Purple Vienna, Grand Duke, Gigante (also known as Superschmelz), Purple Danube, and White Danube. Coloration of the purple types is superficial: the edible parts are all pale yellow. The leafy greens can also be eaten.ohlrabi (German turnip or turnip cabbage; Brassica oleracea Gongylodes Group) is an annual vegetable, and is a low, stout cultivar of cabbage. Kohlrabi can be eaten raw as well as cooked.
It is grown for the delicious bulb and its leaves. If you are just interested in eating the leaves, you can harvest kohlrabi at any time that the leaves reach a desirable size. If you want the bulb as well, you should harvest kohlrabi once the bulb reaches a diameter of two to four inches in size. You do not want the bulb to become too large, because then it becomes woody and less desirable in taste. The picture below shows a Purple Vienna kohlrabi bulb that is an ideal size for harvesting.