We mixed icing sugar, baking soda and citric acid to get sherbet. Play with the amounts beforehand and alter to taste.
3 glasses with powders in. Bowl to mix, spoon to mix.
Ask the beavers to predict what might happen? They can taste minute amount of each powder. Why does it fizz on your tongue? (Because the water in your mouth chemically reacts with the bicarb to make co2 bubbles.