Understanding the Science Behind Ice Cream Vendors' Tricks
The Arrival of Summer and the Joy of Ice Cream
As summer approaches, the heat becomes increasingly intense, especially during the afternoons. With rising temperatures, our cravings for cold treats also heighten. Everyone enjoys indulging in ice cream during the hot months. When laziness strikes to head out to the market, ice cream vendors come to our neighborhoods. The moment we hear the familiar sound of their bells, we instantly recognize that the ice cream vendor has arrived.
The Ice Cream Vendor's Cart
The vendor typically has a cart filled with ice, where he keeps all his ice creams. Surprisingly, despite the scorching heat, the ice cream does not melt. This is because he stores the ice cream in a box filled with ice. Logically, one would think that the ice should melt quickly, but it doesn't because he adds salt to the ice.
The Science of Ice and Salt
Many of you might be wondering about the connection between ice and salt. To understand this, we need to delve into the concepts of freezing point, boiling point, and depression in freezing point. These are topics many of you might have encountered in school science classes. If you've forgotten, let’s refresh your memory.
The freezing point is the temperature at which a liquid turns into a solid. For instance, the freezing point of water is 0 degrees Celsius, at which it solidifies into ice. On the other hand, the boiling point is the temperature at which a liquid begins to boil; for water, this is 100 degrees Celsius.
Depression in freezing point refers to the phenomenon where the vapor pressure of a substance decreases when a non-volatile solute is added, resulting in a lower freezing point and a higher boiling point.
Why Salt Prevents Ice from Melting
In simpler terms, adding salt to ice raises its boiling point, which prevents it from melting quickly. Therefore, when the ice cream vendor mixes salt with the ice, he gains a double advantage: the ice does not melt, and neither does the ice cream.
Interestingly, the vendor may not even be aware of the scientific principles behind the increase in the boiling point of the ice he uses daily.