This practical involves students mixing three ingredients to make sherbet; a sweet powder which fizzes on the tongue.
Equipment typically required (per set):
The process required to make sherbet is very simple. The three ingredients are just mixed together in the quantities shown. They should be mixed in a clean cup with a mixing spoon, not lab equipment. Also the sherbet should not be consumed in the science lab for safety and hygiene reasons (see CLEAPSS or SSERC advice)
The quantities of the ingredients can be varied slightly to give a better tasting mixture but be aware that citric acid is an irritant.
- 50g icing sugar
- 1 tbsp bicarbonate of soda
- 1 tbsp food grade citric acid (powder)
- mixing cup
- mixing spoon
How sherbet works
The chemical equation for the reaction is as follows:
citric acid + sodium hydrogen carbonate → carbon dioxide
+ sodium citrate + water
When you taste the sherbet, water in your mouth helps the acid to mix with the bicarbonate of soda, producing carbon dioxide. This bubbling gas feels fizzy to taste and the acid makes the sherbet taste sour.
The sherbet should be stored in an airtight container if not being tasted straight away.
Typical technician preparation time: less than 5 minutes.