How is baking soda and baking powder the same?

No, baking soda is pure sodium bicarbonate, which reacts with acids in other ingredients of a recipe to create CO2 bubbles an lighten the mixture. Baking powder contains sodium bicarbonate and produces CO2 in the same way, but it contains the acid mixed in with it already. Both baking powder and baking soda (which is called bicarbonate of soda in the uk) are used to do the same thing leaven, or lighten up, a recipe. But they are not the same thing.