Cream is made by separating milk into fat-rich cream and an almostfat-free (skimmed) milk. This is usually done by centrifugalforce.
There are many varieties of cream, categorized according to theamount of milk fat in it:
Light cream, also called coffee or table cream, can containanywhere from 18 to 30 percent fat, but commonly contains 20 percent.It can not be whipped.
Whipping cream contains 30 to 36 percent milk fat andsometimes stabilizers and emulsifiers. Whipping cream will double involume when whipped.
Heavy cream, also called heavy whipping cream, is whippingcream with a milk fat content of between 36 and 40 percent. It'susually only available in specialty or gourmet markets.
Half-and-half is a mixture of equal parts milk and cream,and is 10 to 12 percent milk fat, and can not be whipped.
All cream, unless ultrapasteurized (briefly heated to 149°C/300°Fand then cooled), is highly perishable and should be kept in thecoldest part of the refrigerator.
Whipped cream in pressurized cans is a mixture of cream, sugar,stabilizers, emulsifiers and gas, such as nitrous oxide. It isexpanded by the gas into a "puffy" form. Aerosol "dessert toppings,"which are usually made with hydrogenated vegetable oils, haveabsolutely no cream in them (and doesn't taste like cream either).
Source: The food lover's companion by S.T.Herbst.