No, cornstarch and baking powder are not the same. Cornstarch is a fine, powdery starch made from corn, while baking powder is a leavening agent that helps baked goods rise. Both can be used as thickeners, but they have different uses in cooking and baking. Cornstarch is best used as a thickener for sauces, gravies, and pies, while baking powder is typically used in baked goods.