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Your kitchen is a treasure trove of items that can be used to stimulate your child’s interest in Science!
More than just a place to cook meals and store food essentials and snacks, the kitchen contains everyday items, plus cooking utensils that can be used to demonstrate many scientific principles that your child learns in school. If you have a little time during weekends or the holidays, try out these fun experiments… and create yummy snacks at the same time.
 Sparkling Sherbet Candy
Have you or your children eaten tiny packets of coloured candy crytals that go ‘pop and crackle’ on your tongue? These usually go by the name of ‘fizzy candy’ or ‘crackling candy’, and can make quite of noise, which children find great fun. With a few simple ingredients, you can create this candy at home while teaching them about chemical reactions.
You need:
4 tablespoons of icing sugar (confectioners’ sugar)
1 teaspoon of bicarbonate of soda
1 teaspoon of citric acid (get this from baking supply stores or the pharmacy)
Mix the different powders thoroughly in a small bowl to create the sherbet powder, and provide your children with plastic stirrers. In a separate bowl, put 2 tablespoons of icing sugar. Let your child dip a plastic stirrer into each bowl, taste it and ask them these questions
- What does the powder taste like
- How does it feel on your tongue?
While both powders will taste sweet, your children will probably be amazed at the ‘fizzy feeling’ that the sherbet powder leaves on the tongue, compared to the sweet but ‘flat’ icing sugar powder.
What makes the sugar 'tingle'?
This is caused by a chemical reaction on the tongue, when the two dry ingredients - bicarbonate of soda and citric acid - mix with water in saliva, and creates a gas in the form of many tiny bubbles. When these bubbles form and go ‘pop’, they create the ‘fizzy’ and tingling feeling.
To see a similar example of what happens in the mouth when you taste some sherbet powder, gather round the sink and pour a few tablespoonfuls of bicarbonate of soda down the sink hole. Then carefully pour one-third of a cup of vinegar down the hole. You will immediately see a fizzing reaction, with lots of foamy white bubble forming and rising up from the sink hole. By the way, this is also an old-fashioned, natural way to unclog and clean your sink pipes : )
To make your own coloured sherbet candy for parties and presents, replace the icing sugar with larger sugar crystals such as castor sugar or fine sugar, and add a few drops of colouring before using a food processor to break up the sugar crystals into a very fine powder. Add the bicarbonate of soda and citric acid to this powder and you have your own sherbet candy! You can roll small pieces of hard candy in the sherbet powder to create fizzy candy pieces, or pour teaspoonfuls of the powder into cold water to create a fizzy sherbet drink. Store the sherbet powder and candies in a dry place.
Note: While fun to eat, go easy on the sugar intake, drink lots of water, and make sure the kids brush thoroughly after eating : )
Pop-pop-pop-Popcorn!
If you’re an avid cinema-goer, the image of popcorn may just pop into your head at the mention of movie snacks! But at a fraction of the cost of a small bag of popcorn at the nearest Cineplex, you can make a big pot of homemade popcorn while teaching your child about volume, states of water and expansion.
You need:
A large heavy pot with two handles, and a tight-fitting lid that is preferably made of glass
Half a cup of dry popcorn kernels (from the dry goods section of the supermarket)
A stovetop gas / electric cooker
Place the pot on a gas / electric hob and switch it on to medium heat. When the base of the pot is hot (you can feel heat radiating from the base), pour the kernels into the pot and close the lid. If it is not tightfitting, keep one hand on the lid handle (be careful not to burn yourself!). Every ten seconds, hold the pot via the two handles and give it a good swirl to move the kernels around.
 Have your child sit watch from a safe distance (sitting on a high stool if need be), where he or she can look through the clear lid of the pot and see the kernels below. After 1.5 to 2 minutes, you will start to hear popping sounds. Stop swirling, and watch carefully – you will see freshly popped corn jumping about in the pot. Get your kids to count the number of pops – this can be great fun! The pops will speed up until they become difficult to count, and then finally slow down to less than 1 pop per second. When this happens, switch off the fire but continue to swirl the pot once in a while – some corn kernels will continue to expand and pop for a minute or so.
What makes the popcorn ‘pop’?
Each yellow kernel contains a tiny amount of moisture in its starchy centre. When the kernel is heated to above 100 degrees Celcius, the water in the centre of the kernel will change its state and become steam. Steam has a much higher volume compared to water, and would occupy 1200 times the amount of space compared to the same mass of water! Therefore, once the moisture in the kernel is converted to steam, it will try to expand the kernel to make more room for the steam. However, as the outer layer of the kernel, called the hull, is very tough. It cannot expand and instead breaks the skin like a mini ‘explosion’ when there is enough pressure inside the kernel. Now the steam can escape, and what you get are crunchy, chewy popcorn pieces instead of a tiny hard piece of corn kernel. In every batch of corn, there will be some kernels which are drier than the rest, and lose all the moisture inside them. Therefore, they will not pop, and that is why you will always see a few unpopped corn kernels at the end of your popcorn experiment.
Once the popcorn has cooled a little, you can drizzle a little melted butter or honey on it, or have it plain as a yummy snack while watching a movie in the comfort of your home.
Can you suggest other fun and safe experiments to try out in the kitchen? Share with us!
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