Dennis Wayne Elledge, age 13, of Greenwood, Va., for his question:

WHAT IS BAKING SODA?

Soda is the common name for a group of compounds that contain sodium. The various sodium compounds are manufactured from common salt, which is made up of sodium and chloride.

The popular soda used in cooking and also known as baking soda or saleratus is actually sodium bicarbonate.

Baking powder, often used in baking, contains sodium bicarbonate. This addition acts as a leavening agent because it causes bread, biscuits and pastries to rise in baking. Seidlitz powders also contain sodium bicarbonate. They relieve excess stomach acid.

Another soda related to sodium bicarbonate is sodium carbonate, which is also called sal soda. It has a strong alkaline reaction which means that it neutralizes acids.