Why We Use Salt on Roads
Winter makes roads dangerous. Ice covers streets. Cars slip. People fall. Cities use salt to fix this.
How Water Freezes
Water turns into ice at 0°C (32°F). Molecules move slowly. They lock together. This creates a solid block.
The Salt Trick
Salt is sodium chloride. When salt hits ice, it dissolves. It breaks into tiny parts: sodium and chloride ions. These parts get between water molecules. They stop ice from forming.
This process is called "freezing point depression." Salt lowers the temperature where water freezes. With salt, water stays liquid below 0°C. It might need -10°C or colder to turn into ice.
Why Salt Works Best
Salt is cheap. It is easy to find. It is safe to handle. It melts thin layers of ice quickly.
Important Limits
Salt stops working in very cold weather. If the air is -15°C, salt cannot melt the ice. Also, salt hurts plants. It can rust car metal. Cities use it carefully.
Summary
- Ice is slippery.
- Salt mixes with water.
- Salt makes freezing harder.
- Roads stay wet, not icy.
Science makes travel safer.
Do you use salt on your driveway in winter?