Because hard margarine has been hardened by reacting it with hydrogen, whilst soft margarine hasn't.
You can substitute margarine for butter in all types of baking.
The major difference is in the formulation, specifically the ratio of saturated to unsaturated fats. Hard margarine will have a higher ratio of saturated to unsaturated fat and therefore will be more solid at room temperature. Soft margarine (sometimes called spreadable margarine) will have a lower ratio of saturated to unsaturated fat and therefore will be less solid at room temperature. At high temperatures (think summer with no A/C), soft margarine may start to separate into liquid and solid phases as the unsaturated fats melt and float to the surface.
Each stick of margarine equals one-half cup. So it would take 1 1/2 cups soft margarine to equal 3 sticks.
Yes you can buy margarine in the UK. It exists in the original quite hard form which is good for use in baking cakes and pastries and also in the more modern soft form which you can spread straight from the refrigerator.
Hard
Whether you choose to use butter or soft margarine for a cake, all of your cake ingredients should be room temperature. Margarine or butter needs to be room temperature to make it easier to cream. If it is too cold, or too warm, the cake won't rise properly. Creaming the butter with room temperature butter or margarine allows air to incorporate into it properly.
Came with a separate package of a coloring agent which you had to add and mix in yourself. Yellow margarine could not be purchased. Butter was yellow, margarine was white. Lard was white. Yellow was a premium product and laws were passed to insure that you couldn't peddle lard or vegetable oils as the Real Thing.
it is hard and sometimes soft
hard
soft you can bend and hard you can not
Hard to answer as it's hard to see what you are trying to ask. Obviously it's not a prediction, which is a forecast, but I can't think what word you really intended. Margarine is primarily a blend of vegetable oils.
why metallic solids are soft to hard