Boiling cold water In a Vacuum Chamber

Summary

In this video, a demonstration showcases the process of boiling water at room temperature using a vacuum chamber. By reducing the atmospheric pressure, the presenter successfully lowers the boiling point of water, making it boil at around 15°C. The experiment also highlights how the temperature of the water drops as it boils, demonstrating the endothermic nature of evaporation. The video provides a clear explanation of the relationship between pressure, temperature, and boiling, making it an informative experiment in thermodynamics.

Takeaways

• 🔬 The experiment demonstrates boiling water at room temperature by reducing atmospheric pressure.
• 🧪 Avogadro's law is mentioned, which relates the volume and number of gas particles, affecting pressure.
• 🌡 A thermometer is used to show the temperature of the water, starting at around 23 degrees Celsius.
• 💧 The water is initially evaporating at a low rate due to some molecules having enough energy to overcome intermolecular forces.
• 🚫 The vacuum pump is used to remove gas molecules from the chamber, lowering the pressure above the liquid.
• 🌀 Boiling occurs when the vapor pressure equals the atmospheric pressure, allowing gas molecules to escape.
• 📉 As the pressure is lowered, the water's boiling point decreases, and it begins to boil at lower temperatures.
• 🤔 The temperature of the water actually drops during the process, indicating an endothermic process where heat is absorbed.
• ❄️ The experiment shows water boiling at 15 degrees Celsius, challenging the traditional boiling point.
• 🔄 After boiling, the pressure is allowed to return, and the temperature of the water is observed to have decreased significantly.
• ❄️ The energy for boiling comes from the water itself, causing the temperature to drop as the fastest-moving molecules escape.

Q & A

What is the main purpose of the demonstration in the script?

The main purpose of the demonstration is to show that water can be made to boil at room temperature by lowering the atmospheric pressure.

What is a vacuum chamber and how is it used in this experiment?

A vacuum chamber is a container from which air has been removed to create a low-pressure environment. In this experiment, it is used to lower the pressure above the liquid water to facilitate boiling at a reduced temperature.

What is Avogadro's law and how does it relate to the experiment?

Avogadro's law states that the volume of a gas is inversely proportional to the pressure when the temperature is held constant. In the experiment, lowering the pressure above the water causes the volume of the gas above it to increase, leading to boiling at a lower temperature.

Why does the water start to boil at a lower temperature when the pressure is reduced?

The water boils at a lower temperature because the reduced atmospheric pressure allows the vapor pressure of the water to equal the external pressure at a lower temperature, which is the condition for boiling.

What is the significance of the thermometer in the experiment?

The thermometer is used to measure the temperature of the water. It shows the temperature at which the water starts to boil as the pressure is reduced.

What is the relationship between the atmospheric pressure and the boiling point of water?

The boiling point of water is directly related to the atmospheric pressure. Higher pressure requires a higher temperature for water to boil, while lower pressure allows water to boil at a lower temperature.

Why does the temperature of the water decrease during the experiment?

The temperature decreases because the boiling process is endothermic, meaning it absorbs heat. As the water molecules gain enough energy to escape into the gas phase, they take energy away from the remaining water, causing its temperature to drop.

What happens when the vacuum pump is turned off and the pressure is allowed back in?

When the pressure is allowed back in, the water stops boiling and the temperature of the system may stabilize or change depending on the new pressure conditions.

What is the significance of the term 'evaporation' in the context of this experiment?

Evaporation refers to the process where water molecules with enough energy to overcome the attractive forces between them escape into the gas phase. In the experiment, the rate of evaporation increases as the atmospheric pressure is lowered.

What does the experiment demonstrate about the relationship between pressure and phase changes?

The experiment demonstrates that by lowering the atmospheric pressure, the phase change from liquid to gas (boiling) can occur at lower temperatures, showing that pressure plays a crucial role in phase transitions.

What is the final temperature of the water after the experiment, and what does this indicate?

The final temperature of the water is around 14 degrees Celsius. This indicates the amount of energy the water lost during the endothermic process of boiling at reduced pressure.

Outlines

00:00

🔬 Boiling Water at Room Temperature

This paragraph describes an experiment where water in a beaker with a thermometer is placed in a vacuum chamber connected to a pump. The purpose is to demonstrate Avogadro's law and the effect of pressure on boiling. The presenter explains that by reducing the atmospheric pressure, the boiling point of water can be lowered, allowing it to boil at room temperature (around 23 degrees Celsius). The process involves the evaporation of water molecules with enough energy to overcome intermolecular forces. As the pressure is lowered, the rate of evaporation increases, and eventually, the water boils at a lower temperature than normal. The experiment also notes a decrease in temperature during the process, indicating that boiling is an endothermic process where the environment gets colder due to the energy required for the phase change.

05:01

🌡️ Temperature Change During Boiling

In this paragraph, the focus is on the temperature change observed during the boiling process. Initially, the water's temperature was around 23 degrees Celsius, but as the water boiled at reduced pressure, the temperature dropped to 14 degrees Celsius. This significant temperature drop illustrates the energy loss due to evaporation, emphasizing that boiling is an endothermic process. The summary also mentions the experiment's conclusion, where the water boiled at an even lower temperature of 15 degrees Celsius, and the subsequent reintroduction of atmospheric pressure to observe any changes. The paragraph concludes with a reflection on the energy dynamics of the process, noting that the fastest-moving molecules are the ones leaving due to the lower pressure.

Keywords

💡Water

Water is a simple compound of hydrogen and oxygen and is essential for all known forms of life. In the video, water is the substance being manipulated within a beaker to demonstrate the effects of pressure changes on its phase state. The script mentions water's evaporation and boiling, which are central to the experiment's aim of achieving boiling at room temperature by lowering atmospheric pressure.

💡Beaker

A beaker is a type of laboratory glassware used for holding liquids. In the context of the video, the beaker contains water and a thermometer, serving as the primary vessel for the experiment. It is placed in a vacuum chamber to facilitate the demonstration of the effects of reduced pressure on the water's boiling point.

💡Thermometer

A thermometer is an instrument used to measure temperature. In the video, the thermometer is placed in the beaker to monitor the temperature of the water as the atmospheric pressure is lowered, illustrating the relationship between pressure and the temperature at which water boils.

💡Vacuum Chamber

A vacuum chamber is a container whose pressure can be significantly reduced from atmospheric pressure. In the script, the vacuum chamber is used to create a low-pressure environment for the water in the beaker, demonstrating Avogadro's law and the effect of pressure on the boiling point of water.

💡Vacuum Pump

A vacuum pump is a device that removes gas molecules from a chamber to create a vacuum. In the video, the vacuum pump is connected to the chamber containing the beaker of water to reduce the air molecules and lower the pressure, which is a key step in the experiment to achieve boiling water at room temperature.

💡Avogadro's Law

Avogadro's law states that the volume of a gas is inversely proportional to its pressure when the temperature is held constant. The script references this law to explain the relationship between the reduction of gas particles and the decrease in pressure within the container, which is a fundamental concept in the experiment.

💡Pressure

Pressure is the force exerted per unit area. In the context of the video, atmospheric pressure is the force exerted by the weight of air molecules above the water in the beaker. The experiment involves reducing this pressure to demonstrate how it affects the boiling point of water.

💡Evaporation

Evaporation is the process by which molecules in a liquid state transition into a gaseous state. The script describes how water is evaporating at room temperature due to molecules having enough energy to overcome attractive forces, which is a precursor to boiling in the experiment.

💡Boiling Point

The boiling point is the temperature at which a liquid turns into a gas at a given pressure. The video's main theme revolves around altering the boiling point of water by changing the atmospheric pressure, aiming to demonstrate boiling at temperatures significantly lower than the normal boiling point.

💡Endothermic Process

An endothermic process is one that absorbs heat from its surroundings. The script mentions that boiling is an endothermic process, which is why the environment gets colder as the water loses energy to the evaporation process during the experiment.

💡Vapor Pressure

Vapor pressure is the pressure exerted by a vapor in equilibrium with its condensed phases at a given temperature in a closed system. The script refers to the point where the vapor pressure equals the atmospheric pressure, which is when boiling occurs, as demonstrated when the water boils at a much lower temperature than expected.

Highlights

Demonstration of boiling water at room temperature by lowering atmospheric pressure.

Explanation of Avogadro's law relating to pressure and volume with a decrease in gas particles.

Setup of a vacuum chamber to remove air molecules and lower pressure.

Evaporation of water at room temperature due to molecules with enough energy to overcome intermolecular forces.

Attempt to achieve boiling without increasing temperature by manipulating atmospheric pressure.

Boiling point is the equilibrium between gas molecules escaping and atmospheric pressure.

Observation of water evaporating without boiling due to high atmospheric pressure.

Activation of the vacuum pump to reduce pressure and initiate the boiling process.

Denting of the glass chamber as a visual indicator of gas molecules being removed.

Evaporation rate increase as atmospheric pressure decreases.

Unexpected temperature drop during the boiling process.

Boiling observed at 21 degrees Celsius due to reduced atmospheric pressure.

Theoretical explanation of Le Chatelier's principle and its application in this experiment.

Visual confirmation of water boiling at 15 degrees Celsius.

Restoration of atmospheric pressure to observe the system's reaction.

Post-experiment temperature reading of 14 degrees Celsius, indicating energy loss during boiling.

Discussion on the endothermic nature of the boiling process and its environmental impact.

Transcripts

in this demonstration I am taking water

that's in a beaker and it has a

thermometer in it and it's going to be

placed in something called a vacuum

chamber so as I pan back out here you're

gonna see that I have I connected it

connected that apparatus to a vacuum

pump which is going to pump out the air

molecules Avogadro's law states pressure

or at least the volume decreases with

number of particles but as we lower the

number of gas particles in the container

I'm gonna lower the pressure so what I'm

trying to do is and I put the top back

on and seal it here what I'm gonna try

to do is take out the gas molecule so

I'm gonna try to lower the pressure

above the liquid we know the liquid

right now is evaporating because it does

have molecules that have enough energy

to overcome the attractive forces

between them and we know it's

evaporating but at a low rate and we're

trying to get boiling here we're trying

to boil water at room temperature you

can read the thermometer is about 23 or

so hard to read through the the glass

chamber but it's about 23 and we're

gonna try to boil this water at room

temperature about 23 degrees Celsius by

lowering the atmospheric pressure that's

all I'm trying to do here because we

know that boiling is when the

atmospheric pressure upward which is the

gas molecules escaping into the gas

phase equal the atmospheric pressure

pushing down when those two forces are

equal we get boiling so you say the

blunt point of water it can be any

temperature so I'm trying to prove that

so let me turn on the vacuum pump lower

the pressure and right now this water is

evaporating it is going from a gas

liquid phase to a gas phase right now we

don't see it because you can't see steam

but it's not boiling because the

atmospheric pressure is too large so

we're gonna lower the atmospheric

pressure right now

and I'm pointing out the dents mark is

and once I drive out all the gas

molecules they'll be less molecules to

collide with the surface less force

pushing down the surface and I said

achieve a maximum rate of evaporation

that wins you can choose seat starting

and happy now and there's our woman now

wants to take careful look at the

temperature of the system it's actually

falling a little bit you need to say

well why is the temperature dropping

we're boiling at 22 degrees Celsius 21

degrees Celsius

very interesting the properly boil at 1

degree Celsius because for Lea's limit

at least that's your equal to vapor

pressure and at 21 degrees Celsius

introducing a lot of pressure

you've got boiling you look carefully

though the temperature is dropping the

temperatures getting under the water is

getting cooler as important the

operation of only the n-doped in the

process we're not applying any be here

what where's the energy coming from to

make this is losing the molecules that

are moving the fastest are leaving as

dennis molecules because of the lower

courts as well as

okay

[Music]

[Music]

this man alright and we made water boil

at 15 degrees Celsius what I'm gonna do

now is I'm going to let the pressure

back in and see what happens okay I

don't think I saw any freezing but let's

see if we can read that thermometer any

better okay so the energy that was used

to boil okay

is being used and then he got pretty

cold so if you look at our thermometer

we're still about 14 degrees Celsius so

we were at 23 and we're down to 14 that

showed us how much energy the water lost

to the evaporation member evaporation

boiling is an endothermic process the

environment gets colder