What is the freezing point of water in celsius?

The freezing point of water is 0 degrees Celsius.

This is the exact temperature where liquid water starts turning into solid ice. Here in India, and in most parts of the world, we use the Celsius scale for everything, so this is a very fundamental number for us. You see, the Celsius scale was basically designed around this principle: 0°C for freezing and 100°C for boiling, both at standard atmospheric pressure.

Do keep in mind, this is for pure water. If you add things like salt to it, the freezing point actually drops below zero. It’s the simple reason our freezer compartments at home are always set to a much colder temperature than 0°C

While 0°C is the standard answer, it's not always true. This value is for pure water under standard pressure. Two key factors can change the freezing point:1. Impurities (Salt/Sugar): When you dissolve a substance like salt or sugar in water, you create a solution. The dissolved particles interfere with the formation of the rigid crystalline structure of ice. This lowers the freezing point. This is why we salt roads in winter—to prevent ice from forming even when the air temperature is below 0°C. Seawater, which contains salt, freezes at around -2 °C.2. Pressure: Increasing pressure generally lowers the freezing point of water, but only very slightly. It takes a tremendous amount of pressure to change it by even a single degree. This is why the effect of pressure is often negligible for everyday situations, but it is a critical factor in certain geological and engineering contexts.So, for your glass of tap water, it's 0°C. For ocean water or a brine solution, it's lower.

Here's a cool scientific nuance: the freezing point and the melting point are the same temperature—0°C. This is known as a phase equilibrium. At exactly 0°C and 1 atm pressure, water and ice can coexist. If you add heat energy to the mixture, it will melt the ice without changing the temperature. If you remove heat energy, it will freeze the water, again without changing the temperature. The energy required for this phase change is called the latent heat of fusion. This is why a slurry of ice and water is such a stable thermal reference; it will stubbornly remain at 0°C until all of one phase is converted to the other. This principle is used in calibrating thermometers.

The freezing point of water is 0 degrees Celsius (°C). This is a fundamental constant that serves as one of the two defining fixed points on the Celsius temperature scale itself. The scale was designed by Anders Celsius in 1742, originally with 0 degrees as the boiling point of water and 100 degrees as the freezing point. It was later reversed to the convention we use today. Therefore, under standard atmospheric conditions (at sea level with an air pressure of 1 atmosphere), pure water will transition from its liquid state to its solid state (ice) at precisely 0 °C. This value is a cornerstone of thermodynamics, meteorology, cooking, and countless scientific and everyday applications. It's the baseline from which we understand cold weather, freezer temperatures, and phase changes.

From a practical, everyday perspective, knowing the freezing point is crucial for: Weather Forecasting: Those below-freezing temperatures in the forecast tell you to watch for ice on the roads and frost on your windshield. Cooking & Food Safety: Your freezer should be set to at least -18°C to properly preserve food, well below the freezing point to ensure rapid freezing and prevent bacterial growth. Recipes for sorbets and ice creams rely on depressing the freezing point with sugar. Science Experiments: It's a basic reference point for students learning about states of matter. Engineering: Preventing water from freezing in pipes is a major design consideration in cold climates.So, while the answer seems simple, this one number—0—is deeply embedded in how we interact with and understand our physical world.