¿SE PUEDE HERVIR AGUA CON LA GRAVEDAD? Diagrama de fases del AGUA - TERMODINÁMICA

Summary

In this fascinating video, the concept of the water phase diagram is explored, revealing how water's boiling and freezing points change with pressure. The video explains how at higher altitudes, the boiling point decreases, and at higher pressures, it increases. It delves into the unique behavior of water at the triple point and demonstrates an experiment where water boils at room temperature by creating a near-vacuum with gravity. The video also touches on supercritical fluids, explaining how liquid and gas phases mix beyond a critical point, with the potential to seamlessly transition between states without distinct phase changes.

Takeaways

• 😀 The boiling point of water is affected by atmospheric pressure. At sea level, it boils at 100°C, but at higher altitudes, it boils at lower temperatures.
• 😀 Pressure affects the state of water: at high pressure, water boils at a higher temperature, while at low pressure, it boils at a lower temperature.
• 😀 The water's phase (solid, liquid, gas) depends not only on temperature but also on pressure, as shown in the phase diagram.
• 😀 At the triple point, all three states (solid, liquid, gas) of water coexist at the same temperature and pressure, which is a fascinating phenomenon.
• 😀 In extremely low-pressure environments (like outer space), water can sublimate directly from ice to vapor without becoming liquid.
• 😀 The concept of pressure can be used to cook food at higher temperatures, such as using a pressure cooker, which allows water to boil at higher temperatures and cook food faster.
• 😀 By creating a vacuum using gravity, water can be made to boil without external heat, as demonstrated by using a long water-filled hose and lowering one end.
• 😀 Water can boil at room temperature if the pressure is lowered sufficiently, as illustrated in the demonstration where water boils at 20°C when pressure is reduced.
• 😀 The effect of supercritical fluids is highlighted, where liquid and gas phases merge and become indistinguishable under specific pressure and temperature conditions.
• 😀 The supercritical state of water occurs at pressures above 221 atm and temperatures over 374°C, where liquid and gas properties blend seamlessly.

Q & A

What is the main concept being explained in this video?

The video explains the phase diagram of water and how changes in pressure and temperature affect its state, including how to boil water using gravity without heating it.

How does atmospheric pressure influence the boiling point of water?

At one atmosphere of pressure, water boils at 100°C. However, as atmospheric pressure decreases (e.g., at high altitudes), the boiling point decreases. Conversely, when pressure increases, the boiling point rises.

What happens to water at the top of Mount Everest regarding boiling?

At the top of Mount Everest, the atmospheric pressure is much lower, causing water to boil at a temperature of around 86°C instead of the standard 100°C.

Why does pressure affect cooking, such as when using a pressure cooker?

A pressure cooker increases the pressure inside, allowing water to boil at a higher temperature, such as 120°C, which cooks food like lentils faster.

What is the significance of the triple point in water's phase diagram?

The triple point is where the solid, liquid, and gas phases of water coexist at the same temperature and pressure. It's a unique condition where water can freeze and boil simultaneously.

How does the pressure below the triple point affect water?

Below the triple point (at pressures lower than 611 Pascals), water can bypass the liquid phase and go directly from solid (ice) to gas (vapor) in a process known as sublimation.

What experiment demonstrates boiling water using gravity?

The experiment involves creating a low-pressure environment by lowering a bottle of water down a 10-meter column. This reduces the pressure in the container, causing the water to boil without heating it.

How does the concept of vacuum relate to the water boiling experiment?

In the experiment, the water boils when the pressure inside the container is reduced, simulating a vacuum. The water begins to boil at a lower temperature due to the decrease in pressure, even though it remains at ambient temperature.

What are supercritical fluids, and how do they differ from regular liquids and gases?

Supercritical fluids are substances that are at a temperature and pressure beyond their critical point. They exhibit properties of both liquids and gases, where the liquid and gas phases merge into a single, indistinguishable phase.

What is opalescence in the context of supercritical fluids?

Opalescence occurs in supercritical fluids when the liquid and gas phases begin to separate and become distinguishable. Tiny droplets scatter light, making the fluid appear cloudy, like a fog or mist.