Fizzy sherbet in a paper bag with a strawberry lollipop was probably my favorite treat as a child, but I never knew what was in the sherbet and why it sparkled and tingled on my tongue! Try making some with your kids and enjoy a mini science lesson in the process.

The basis of the sherbet is icing sugar (confectioners sugar). 50g will make enough for about 6 children. For that amount you will also need a scant teaspoon each of bicarbonate of soda and citric acid. You can buy the latter, in the form of a white powder, very cheaply in small quantities from your chemist or pharmacy. Children will also enjoy having a lollipop or liquorice stick to dip into the sherbet.

Simply mix all the powders together thoroughly, divide into separate containers, and provide something to dip with. Fingers will do at a pinch, but there will be a lot of stickiness involved! Let the kids try dipping into some plain icing sugar as well as the sherbet mixture, to compare the two. They will be amazed at the difference.

So where does the fizz come from? It is a reaction between the citric acid (the same acid as in lemons) and the bicarbonate of soda, which is an alkali. In this case the chemical reaction happens on your tongue, as the two dry ingredients mix with water (saliva) and create a gas in the form of lots of tiny little bubbles. The bubbles provide the tingle in your mouth.

You are creating the same chemical reaction when you drop a bath bomb into your bath water. The active dry ingredients which again include bicarbonate of soda and citric acid react when they meet the water of the bath. And you get the same fizzing reaction if you add vinegar, another acid, to bicarbonate of soda. In this case, however, the reaction happens immediately because the vinegar is liquid. Combining vinegar and bicarbonate of soda is actually an old-fashioned cleaning recipe, used to help remove stubborn stains in the kitchen. Perhaps your kids could try scrubbing the sink with the mixture and a kitchen sponge to see how well it works!

Now, back to your fizzy sherbet. Remember, to keep your sherbet for any length of time, you will have to keep it dry. Store it in little re-sealable plastic bags ready to dip, or in a plastic food container. Make sure the kids dont eat too much in one go, because it can make your mouth (and stomach) a little sore in very large quantities! If you package little bags of sherbet and lollipops together (perhaps adding a bright ribbon and label) you can make a super addition for a party bag or even an unusual and popular treat to sell at a school fete or other fundraising occasion.