Bubble & fizz

Put some fizz in your drinks - Bubbles in fizzy drinks are carbon dioxide gas which is pumped into the liquid before the can or bottle is sealed. When you open the container the pressure is reduced and the gas bubbles out. You can make you own ‘fizzy drinks’ (remember Creamola Foam?).
 

Figure 9a - Remember Creamola foam?

We would recommend that these recipes are made up by the teacher and that the products are not tasted. Wear safety goggles and disposable gloves during preparation as powdered citric acid is a severe eye irritant.

Figure 9b - Bubbles in a fizzy drink

Put six teaspoons of citric acid crystals (available from a pharmacist) and three teaspoons of baking soda into a bowl. Using the back of a spoon, grind the two substances together to make a powder then add two tablespoons of icing sugar. Two teaspoons of this “Fizz Mix” added to a glass of still water will make it fizzy.
Using almost the same recipe, add four tablespoons of icing sugar instead of two to make a powder with the effect of sherbet. When sherbet dissolves in your mouth, the citric acid and baking soda react with the water in the saliva to produce bubbles of carbon dioxide gas on your tongue. Have some proper sherbet for the children to taste.

Making gas - You can produce carbon dioxide gas in the classroom by mixing vinegar (or another acidic liquid such as lemon or grapefruit juice) and bicarbonate powder. Use a filter funnel or a paper cone to fill an uninflated balloon with bicarbonate. Pour vinegar into a one litre plastic bottle until it is about one quarter full. Stretch the neck of the balloon over the top of the bottle and then lift the balloon so that the bicarbonate falls into the bottle. You will see the vinegar start to fizz. The bubbles given off are carbon dioxide and will gradually begin to inflate the balloon.

  Put out that fire