The loud, high-pitched noise from tea kettles has confused scientists for a long time. The physics behind a whistling kettle sounds very interesting to most people. Has the thought of what makes a kettle whistle also crossed your mind?
A kettle whistles because of the vibrations that gather inside. It’s a result of the steam escaping from the small kettle opening. This process is like how a person whistles with a small gap between the lips, forcing the vibrations out. With the water boiling, more steam is released, resulting in a higher and louder sound.
This article covers everything you need to know about how a tea kettle whistles. So, let’s explore the science behind it.
How Does a Kettle Work, and What Causes It to Whistle?
From a larger perspective, how a kettle works and what causes the whistle is quite simple. The steam in the kettle pushes through a little hole and produces the sound.
Only through research can we understand deeply how a kettle whistles and its underlying mechanism.
The Whistling Kettle; An Exploration Into the History
The 19th-century scientists John William Strutt, Lord Rayleigh, and Baron Rayleigh tried to explore the reason behind a whistling kettle.
They discovered that kettle whistles are a result of sound vibrations. Yet, that wasn’t a satisfactory answer.
However, after a century, scientists got to the core of the issue. Dr. Anurag Agarwal and Ross Henrywood, two scientists from Cambridge University, further investigated.
They discovered that a regular teapot has two holes that disturb the steam’s path. As this flow is blocked, a whistling sound is created.
The scientists used Dr. Agarwal’s prior research about jet engines and how they get their sound. They applied this method and worked on the tea kettle. After knowing the source, they could point out the mechanism for why a kettle only whistles.
The Steps to How a Kettle Whistles
A regular kettle has two plates placed near one another. This creates a small space between both. Each plate has a hole at the center, allowing the steam to go through it.
When you put the kettle to boil, steam starts collecting inside. This steam will first meet the hole present in the kettle spout. The hole, being smaller than the spout, forces the steam to move through. The narrow opening results in a “naturally unstable” steam jet.
You can think of it as a water stream moving from a garden hose. Once it moves a specific distance, it breaks into droplets.
The unstable jet stream moves to the second hole where it cannot properly escape. As a result, as it hits the second wall, a tiny pressure pulse is created.
As it goes through the whistle section, the pulse makes a seam vortices which give rise to sound waves.
What do sound waves represent? That whistling sound you hear from the kettle that your tea or coffee is brewing!
Do All Tea Kettles Whistle?
Not every tea kettle will whistle; whistling tea kettles work with a unique mechanism.
Indeed, whistling kettles have a special system fit on their spout. That makes the whistle sound as air moves through it. It’s much like how an ordinary whistle works.
As your kettle water boils, steam escapes through the kettle’s small opening. That creates a whistle-like use. With the lid closed, the steam cannot escape anywhere else.
If you don’t have a kettle with this mechanism, it won’t whistle. It also won’t whistle if you don’t close the lid of your kettle tightly.
Additionally, electric kettles support the automatic off feature which turns the kettle off automatically when the water is boiled.
Most people use electric kettles today and guess what? These kettles are quick and efficient, boiling the water in only a few minutes.
5 Benefits of Using an Electric Kettle
Electric tea kettles are a popular choice today. That is because of the various benefits it has for users!
1. Quick Use
One of the easiest things is that you don’t need to leave electric kettles on the stove to heat them. Plug them in a socket and get boiling water within minutes.
2. Saves Energy
Electric kettles are also energy efficient; research says up to 80%.
3. More Affordable & Safe
If you’re a coffee or tea lover, you will save a lot of money with an electric kettle. For safety reasons, electric kettles turn off automatically once the water boils. That will protect you from harm.
4. Multiple Purposes
Other than being multipurpose, electric kettles are very easy to handle. You can efficiently heat liquids, like water or milk.
Coffee and tea lovers know water loses its taste if it boils for too long. Electric kettles heat your fluids quickly, so you can always get the best-tasting hot drinks.
Electric kettles don’t only brew your water quickly; you can carry them around. You can get hot coffee anywhere and anytime if you’re on a camping trip or a journey with your family.
How Loud is a Tea Kettle?
How loud your kettle will sound depends on the type you have. Those who tested the sound of a whistling kettle believe the sound to be between 79 to around 95 decibels.
Do you know that this sound is higher than a lawn mower and vacuum cleaner, which lies at 90 and 83 decibels? Yet, some other kettles sound way louder than the electric drill!
Below is a table showing the loudness of different objects to help you get a better idea of how loud a kettle can be.
|Normal Breathing||10 Decibels|
|Electric Drill||95 Decibels|
|Normal Human Speech||60 to 65 Decibels|
|Vacuum Cleaner||83 Decibels|
|Lawn Mowers||90 Decibels|
|Kettle||79 to 95 Decibels|
Is There a Tea Kettle That Boils Quietly?
Most people aren’t bothered by the gurgling noises a kettle makes as it boils. Yet, a quiet kettle is always better if you live with your family or prefer making a cup of coffee in the middle of the night.
What makes a kettle noisy is the way it works. As the water starts heating, it produces bubbles. As these bubbles reach the top of the kettle, they pop, making gurgling noises.
The good thing is not all kettles have to be as noisy. Luckily, you’ll find many kettles in the market today that aren’t at the louder end.
Specialized kettles by Russel Hobbs are around 70 to 75% quieter than a regular kettle. If you want a quiet kettle, these are a good option!
What Makes a Kettle Boil Quietly
Kettles on the quieter end have a unique coating on the inner side. This extra layer ensures that smaller bubbles are produced as the water boils. When smaller in size, these bubbles make less noise as they travel to the top of the kettle.
Besides, some kettles have a dual wall construction. That offers insulation and reduces the sound as your water boils.
The 19th-century mystery of why a tea kettle whistles have recently been solved.
So, now you can stop thinking about why your tea kettle made that whistling sound and relax and enjoy your steaming cup of beverage.
Oh, and if you’re wondering what tea kittle I use, here is the model 👉 VONIKI 12 cups (available on Amazon.com).
- Daily Mail: Why does a kettle whistle
As the founder of Container FAQs, my goal is to provide readers with in-depth information on the containers used in daily life and related subjects. Don't hesitate to reach out to me if you have any suggestions for articles you would like to see on my blog.