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| How To Make Your Own Delicious Swaying Ice |
In previous posts, we have discussed some benefits of salt as the most common example of chemical substance we encounter every day. Perhaps some of you who live in the four seasons countries already used to salt function as snow thinners on the street or prevent the ice formation on the car windshield during winter. We have never actually seen the use of salt directly by ourselves, because we live in the tropical country, Indonesia. But hopefully one day we can set up our foot in the four season’s country immediately. Well now we will discuss the most common function of salt in the process of making ice or ice cream.
Our country
Indonesia has two season that was dry and rain. As the summer, ice or ice cream
becomes the most wanted dish that can relieve our dry throat due to the hot
weather. The one that caught our attention to discuss this salt function was
the memories from our elementary school, when we buy an ice sold by itinerant
sellers who use a wheelbarrow to sell his homemade ice known as ‘es lilin’ or
Swaying ice. What is interesting from this ice is the process of making it
which we had to shaking down the vending carts to make ice freezing quickly.
Before we studied chemistry we had a big curiosity of how the sellers can kept
the ice frozen without any cooler. It is a simply way with simple materials as
well. Mix coconut milk, sugar, salt, flavor and aroma that you can get from
natural ingredients such as fresh strawberries, avocado, durian, jackfruit,
chocolate, green peas or even syrup and essence can be artificial aromas
flavor. All the materials were mixed and cooked until it’s boiled. Once
completed, prepare a rectangular mold and a box containing ice cubes that have
been added salt coarse. Pour the batter into the mold and insert the molding
one by one into the box contain crushed ice cubes. As its name suggest, if you
want it to be quickly frozen, shake it for about 5 minutes then plug the craft
sticks. To make it more delicious, dipped the ice in a melted chocolate.
Actually the
basic principles of the use of salt to melt snow and ice on the streets,
prevent the ice formation on the windshield in the winter were the same which
we used in the making of swaying ice, that was the depression freezing point of
the solution. The ice cubes used in the making of swaying ice first be melted
by the addition of salt then the ice cubes will also adjust the temperature of
the surrounding environment. Ionic bond in the crystals salt form will break
up, this process releasing heat to the environment that was when the ice cubes
melted slowly. Ice fraction that originally had a freezing point around 0°C,
will be melt when salt being added forming salt solution with the freezing
point below 0°C. Freezing point of a solution is the temperature when its vapor
pressure equals the vapor pressure of the solvent. Because of the vapor
pressure of the solution (salt solution) lower than its solvent (pure ice), so
there will be no solution freezing at a temperature of 0oC. Lower
ambient temperature will help the ice to freeze. As you remember, the ice would
melt if it absorbs heat or receiving heat from the surrounding environment. By
lowering the ambient temperature than the freezing point of pure ice, it will
create an environment that allows the temperature of the swaying ice to
decrease and slowly begins to freeze.
