Everyday Science, Everyday Wonder
Simple questions, smart answers.
In winter, frozen roads can be dangerous.
Driving feels like sliding on glass, and walking feels like tiptoeing on thin ice.
But there’s a special white powder that comes to the rescue: Calcium Chloride (CaCl₂).
How does this powder melt ice so quickly?
And why is it much stronger than regular salt (NaCl)?
Let’s uncover the science behind it.
.The Magic of Lowering the Freezing Point
Pure water freezes at 0 °C (32 °F).
But when we sprinkle calcium chloride on ice, the story changes.
When calcium chloride dissolves in water, it splits into three ions:
-
One calcium ion (Ca²⁺)
-
Two chloride ions (Cl⁻)
These ions interfere with water molecules trying to form ice crystals — like breaking up a crowd before it can gather.
Regular salt also lowers the freezing point, but calcium chloride creates more ions, which means a much bigger effect.
In fact:
-
Calcium chloride can lower the freezing point to about -50 °C (-58 °F).
-
Salt works only down to about -20 °C (-4 °F).
That’s a huge difference in cold climates.
Heating Things Up – Literally
Here’s another superpower:
When calcium chloride dissolves in water, it releases heat (an exothermic reaction).
This small burst of warmth helps melt ice faster — like placing a mini hand warmer right on the ice.
Salt doesn’t do this, which is one reason calcium chloride works so well.
Pulling in Moisture to Work on Its Own
Calcium chloride also loves water — it absorbs moisture from the air.
This means it can start dissolving even without direct contact with liquid water.
As it absorbs moisture and begins to dissolve, it releases heat again, speeding up the melting process.
A True Winter Hero – With a Warning
Calcium chloride works in very low temperatures and clears ice faster than salt.
That’s why it’s often the top choice for keeping winter roads safe.
However, using too much can cause corrosion on cars and damage to roadside plants.
The key is using the right amount.
Wrapping Up
Now you know why calcium chloride often replaces regular salt in winter road care.
It’s the invisible superhero keeping icy streets safer for everyone.
Next time you see white powder scattered on a snowy road, remember — it’s not just “road salt.”
It’s a carefully designed scientific solution at work.
댓글
댓글 쓰기