What's the difference between using soda bicarbonate and baking powder while cooking?

They certainly are not the same, spoken as someone who once used soda instead of powder. I never really knew the difference but your question inspired me to look it up. Answer here: http://chemistry.about.com/cs/foodchemistry/f/blba...

Basically baking soda starts acting immediately as soon as it is put in, while powder is "double acting": it has a reaction when added and a second when heated.

When to choose which: here is the pertinent quote from the referenced web page:

"Some recipes call for baking soda, while others call for baking powder. Which ingredient is used depends on the other ingredients in the recipe. The ultimate goal is to produce a tasty product with a pleasing texture. Baking soda is basic and will yield a bitter taste unless countered by the acidity of another ingredient, such as buttermilk. You'll find baking soda in cookie recipes. Baking powder contains both an acid and a base and has an overall neutral effect in terms of taste. Recipes that call for baking powder often call for other neutral-tasting ingredients, such as milk. Baking powder is a common ingredient in cakes and biscuits."

Sodium bicarbonate and baking powder are NOT the same thing. Baking SODA is the same thing as sodium bicarbonate, so if you want to use some Arm & Hammer, it's ok, but baking powder will not give you the results you are looking for as it doesn't contain the same things.

Soda bicarbonate, or Sodium bicarbonate, is just the chemical name of Baking Powder !

...Am an Indian too, and am aware of the Darjeeling, Assam, and Nilgiris varieties of Teas.

But Kashmiri Tea ?! That is a new one.

They are one and the same thing. Some people just like to split hairs when talking.

Bicarb tends to give one the "hershey squirts"

They are the same thing