Powders are solid dosage forms meant for internal or external use, available in crystalline or amorphous forms. They are more stable than liquids but less convenient than liquids. Powders can be simple, containing one ingredient, or compound, containing multiple ingredients. They are prepared through geometric dilution or direct weighing and mixing of ingredients before portioning into individual doses. Effervescent granules are powders meant to be dissolved in water, containing acid substances that react with carbonates to release carbon dioxide.