Boyle's Law Examples in Real Life

Boyle's Law Explained

In 1662, Robert Boyle discovered that when held at a constant temperature, the volume and pressure of a gas are inversely proportionate. Put simply, when the volume goes up, pressure drops, and vice versa.

The mathematic equation is equally as simple: PV=K where P=Pressure, V=Volume, and K is simply a constant.

This has become a basic principle in chemistry, now called "Boyle's law" and is included as a special case into the more general ideal gas law.

Examples in Real Life

You have probably been well acquainted with Boyle's law for most of your life, and haven't even realized it. We experience examples of it on a regular basis. Several times a day, we might use it as a tool, while we also sometimes recognize it as a killer.

Ever filled up a tire? You will generally fill it to somewhere between 30-35 PSI (Pounds per square inch). This is a measurement of pressure. As you put more and more air into the tire, you are forcing all the gas molecules to get packed together, reducing their volume. As long as the air temperature remains the same, you are experiencing a real life example of this law as you watch your PSI change.

Read on for more examples.

Spray paint uses a real life application of Boyle's law to work its magic.
Spray paint uses a real life application of Boyle's law to work its magic. | Source

Spray Paint

While there are a couple different types of aerosol cans, one being a little more elaborate than the other, they both operate off of the same basic principle: Boyle's law. We'll examine the more elaborate of the two, since it's far more popular.

We know that before you spray a can of paint you are supposed to shake it up for a while, listening as a ball bearing rattles around inside. There are two substances inside the can, one being your product (paint for example), and the other being a gas that can be pressurized so much that it retains a liquid state even when it is heated past its boiling point. This liquefied gas will be a substance that has a boiling point far below room temperature. The can is sealed, preventing this gas from boiling and turning into a gaseous state. That is, until you push down the nozzle. The moment the nozzle goes down, and the seal is released, there is now an escape route. The propellant instantly boils and expands into a gas and pushes down on the product trying to escape the high pressure, and expand it's volume the atmosphere where there is less pressure. This forces the product to shoot out from the nozzle, and you have a coat of paint.

The syringe is a textbook example of Boyle's law in action.
The syringe is a textbook example of Boyle's law in action. | Source

Did You Know?

The "Ideal Gas Law" was created as a combination of Boyle's law and Charles's law.

The Syringe

This is far more simple than a can of spray paint. Syringes of all types utilize Boyle's law on a very basic level.

When you pull the plunger out on a syringe, it causes the volume within the chamber to increase. As we know, this causes the pressure to do the opposite, which then creates a vacuum attempting to re-pressurize back to atmospheric levels. Since the only fluid available on the other side of the needle tends to be a liquid such as blood, which gets sucked into the chamber. This then reduces the volume and increases the pressure back to where it wants to be.

Carbonation is what makes soda so delicious. Boyle's law is responsible for spraying it all over your car.
Carbonation is what makes soda so delicious. Boyle's law is responsible for spraying it all over your car. | Source

The Soda Can

Typically we will take a bottle of soda, slowly turning the cap allowing the air to gradually escape before completely removing the lid. We do this because we've learned over time that popping it open too fast causes it to fizz up and spill all over you and everything around you.

Carbonation is exactly what it sounds like. Water is pumped full of carbon dioxide, causing it to bubble up as the CO2 makes its escape. Throw some syrup into the mix, and you have soda pop. When a soda bottle is filled, it is also pressurized. Much like the aerosol can mentioned earlier, when you slowly open the cap, the gas is suddenly able to increase its volume in order to decrease the pressure. Since the soda itself is carbonized, the CO2 gasses decide they want to escape as well, and you have your fizz.

All is fine and dandy, until you shake the bottle up. Shaking up the bottle causes that neat pocket of carbon dioxide gas in the top to mix in with the soda. Now, pop the cap off. Suddenly all of these excess gas bubbles within the soda want to expand and escape their high pressure environment as well. Rather than being able to expand and shoot out of that neat pocket of air with a "pffffffft," they expand while they're still in the soda. As it tries to muscle its way out, it pushes the soda along with. Pressure in the bottle goes down, volume of the gas goes up, and you have yourself a mess to clean up.

"The bends" is a life threatening condition caused when divers don't respect the threat of Boyle's law.
"The bends" is a life threatening condition caused when divers don't respect the threat of Boyle's law. | Source

The Bends

Any properly trained scuba diver knows that when they are ascending from deep waters, a slow ascension is critical. Our bodies are built for and accustomed to living in the normal pressure of our lower atmosphere. As a diver goes deeper underwater, that pressure begins to increase. Water is heavy, after all. With the increase in pressure causing a decrease in volume, nitrogen gasses begin absorbing into the diver's blood.

When the diver begins his ascent, these gas molecules begin to expand back to their normal volume. With a slow ascent, or through the use of a depressurization chamber, those gasses can work their way back out of the bloodstream as they return to their normal volume. Ascend too quickly, however, and his blood becomes a foamy mess. Remember what happens when carbon tries to escape the soda? That same thing is happening in the poor diver's bloodstream. On top of that, any built up nitrogen between the diver's joints will also want to expand. This causes the diver to bend over (where it gets the name) and experience severe pain. In more severe cases, this sudden depressurization of the body can kill a person instantly!

The Cartesian Diver: Build Your Own Boyle's Law

  • By now you either have a basic understanding of Boyle's law and how it can be applied in the real world, or you're suddenly afraid to go swimming.

Either way, this last example of Boyle's law in action is something you can build yourself! Don't worry, it's simple. First you will need a small list of supplies:

  • One 2-liter bottle (clear)
  • One small glass dropper
  • Water

Many don't have the money or time to acquire these supplies. If you fall into that category, you may be able to sell a few things on eBay that have been lying around in a box or attic. Or in a box in the attic.

Once you've managed to gather these supplies, it would be advised to find a handyman or somebody skilled in construction/engineering to assist in deciphering the following steps:

  1. Fill the 2 liter bottle between 2/3 and 3/4 full of water.
  2. Take your eyedropper, the "diver," and fill it with just enough water so that the top of the dropper is just buoyant enough to tread the water.
  3. Apply the lid to the 2 liter bottle. It must be airtight!
  4. Squeeze the bottle.
  5. Observe.

If you have successfully followed the instructions, good for you. Your Cartesian diver should dive to the bottom as you squeeze the bottle. That's Boyle's law in action!

When you squeeze inward, you are reducing the volume of the bottle. As we know, this reduction in volume increases the pressure of all of the gas, including what is contained in your eyedropper.

This increase in pressure pushes against the water, forcing more water up into the eyedropper. As you can see, this additional water decreases the diver's buoyancy, causing it to "dive" to the bottom. Stop squeezing the bottle and everything returns to normal, allowing your diver to ascend back to the water's surface. You would be keen to let go slowly, so your diver doesn't ascend too quickly. Wouldn't want it getting the bends!

One More Thing...

I did leave a certain system out of this list that is used far more than any of the above examples. This system is directly powered by the rules of Boyle's law, and it is a device you use every day, everywhere you go.

What is it?

Comment below, let me know!

© 2012 Steven Pearson

Comments 35 comments

osmund million 3 weeks ago

Cool information really helpful

Sm 8 months ago

Ambu bag

kd 8 months ago

thank you for this site :) I've solved my homework.

Aidan Kittilstved 12 months ago

I think the Mystery Use is the oil storage/injection of a car

melbel profile image

melbel 14 months ago from New Buffalo, Michigan

Awesome idea to show real life examples. It always helps me to see concrete examples of ideas that are being taught. Amazing hub! I would love to see more science hubs like this!

marwa abdallah 15 months ago

Loved the way u make everything appear super simple thanx alot for simplifying my assignment:)

Scott 15 months ago

A great article indeed to satisfy the student and the old, old, student too!

mattforte profile image

mattforte 15 months ago from Spanaway, WA Author

Oh, look at that. Didn't even notice I got HOTD until I was reading these comments lol.

MsLizzy - the correct answer was posted below by Arvedui - it is your lungs ;-)

DzyMsLizzy profile image

DzyMsLizzy 16 months ago from Oakley, CA

Congrats on HOTD! Most interesting. I had never heard of Boyle's Law, although you are correct in its daily effects.

Perhaps you can explain, however, why, if a can of soda pop (only works on CANS, not plastic bottles) gets accidentally jostled just before you open it, by sharply rapping your finger tip on top of the can a few times, you can avoid that explosive event upon popping the top open?

As for the device we use daily wherever we go, I'm going to guess it has to do with cars, and either the carburetor or fuel-injection system.

Voted up ++

Kristen Howe profile image

Kristen Howe 16 months ago from Northeast Ohio

Though I've read this hub a while ago, congrats on HOTD!

vasantha  T k profile image

vasantha T k 16 months ago from Bangalore

Very useful hub for the students and good examples given. Voted up!

RTalloni profile image

RTalloni 16 months ago from the short journey

Congrats on your Hub of the Day award for an interesting post that includes a neat science experiment!

mary615 profile image

mary615 16 months ago from Florida

Congrats on your HOTD~ Very interesting, and I voted it as such. You explained Boyle's Law so I could understand the concept. Thanks.

Kristen Howe profile image

Kristen Howe 18 months ago from Northeast Ohio

This was real interesting to know about Boyle's Law, since I never took chemistry in school. Real great information to know about it. Voted up and useful!

TolovajWordsmith profile image

TolovajWordsmith 19 months ago from Ljubljana

Boyle's law is one of the basic laws in natural sciences, and I think everybody should know it and understand it. It's great to see an explanation with so many real life examples. Great job!

Dan Hath 19 months ago

By the way, great work! I enjoyed your approach in explaining Boyle's law and the many examples that helped me wrap my head around the concept. Sorry for the double post, I had issues going to edit my post so I could add an extra comment in.

Dan Hath 19 months ago

I can't remember what law it is, but Boyle's law sounds like what I was taught takes place in the combustion chamber of a motor. It is a law that has to do with the pressure of the gas air mixture progressively getting higher (and hotter) as the piston of a motor compresses the mixture before it combusts. Diesel motors take advantage of the law as they don't have spark plugs but glow plugs. The intense compression ratio heats up the mixture causing it to ignite near the top dead center cycle of the piston. If it's not Boyle's law, then I am curious to find out what it is. I am also very curious what you are hinting at. As my solution is what takes place in a combustion chamber of an internal combustion motor.

ramya 20 months ago

Wonderful discription

mehmood 20 months ago

thanks a lot ...what a simple description,it helped me a lot for my assignment.

mattforte profile image

mattforte 21 months ago from Spanaway, WA Author


I suppose the wording can be a bit funny. "Volume" in this case isn't necessarily referring to the amount of space inside the tire - but the volume of the gas molecules. As you push more and more air into the tire, the gas molecules are being compressed, thereby reducing the volume of each molecule of gas (not the tire itself), which creates a higher air density.

curious_me 22 months ago

Hi! I liked your article :) It makes science a lot practical to know :) However, I cannot visualize much how filling up tires demonstrates Boyle's Law. How can the volume reduce as pressure is increased? The expansion of the tire indicates increase in volume, right? If this is so, then as air is added to the tire, volume increases and pressure increases as seen in the gauge reading, which defies Boyle's Law. My question is how do I reconcile these contradicting views. Thanks! :)

medini 22 months ago

Thanks for this examples of boyls law ut had helped me a lot :-)♡cool yar♡♡♡

deepthiveera profile image

deepthiveera 2 years ago from Cumbum, Tamil Nadu, India

Very interesting to read all those good examples for Boyle's law. Thank you mattforte, for sharing this scientific truth with nice photos and explanations. Voted Up!

blaze 2 years ago

thakxxx because of this article i can already answer

my assignments

YaraMAriano 3 years ago

Chemistry is everywhere around the globe. Very useful :)

cuttler profile image

cuttler 3 years ago from HubPages much to share with my students here. got just what i needed. thank you for sharing

Michele 3 years ago


mattforte profile image

mattforte 4 years ago from Spanaway, WA Author

Lungs absolutely right! Somebody finally got it! :)

Arvedui 4 years ago


jea alvior 4 years ago

thank you po dahil dito may assignment na ako!!

cclitgirl profile image

cclitgirl 4 years ago from Western NC

Let's see...a system you left out...hyperbaric chamber? Osmosis that happens in the body, you know with the sodium-potassium pumps? The beating heart and the pressure it exerts to make blood pressure?

Anyway, great hub. You could be a physics teacher. I remember doing a unit on Boyle's Law. I don't remember the experiments we did, but I do remember making sine and cosine waves with soda bottles dangling in the air, throwing bowling balls off of school buildings and using a Van der Waal's generator (I think that's how it's spelled) to "electrocute" ourselves. Hehe. Great brought back lots of memories. :)

mattforte profile image

mattforte 4 years ago from Spanaway, WA Author


Nothing to do with a car ;-)


Woops! It was a NASA technician, not an astronaut. My mind was elsewhere as I wrote that apparently. ADHD ftw!


Yes, science is a wonderful thing, and most of it is a lot easier than people generally believe. If we teach concepts, rather than extreme detail and advanced mathematics, then it becomes amazingly simple.

Peggy W profile image

Peggy W 4 years ago from Houston, Texas

It is obvious that you really do like science which I read in your profile. Thanks for the primer on Boyle's Law. Voted up and interesting.

scottcgruber profile image

scottcgruber 4 years ago from USA

Interesting stuff! I hadn't heard about the astronaut who was exposed to space vacuum - who was it?

A more tragic example was Soyuz 11 - three cosmonauts died when their capsule depressurized before reentry.

LisaKoski profile image

LisaKoski 4 years ago from WA

I'm not sure what the last example could be. Maybe something to do with a car?

Anyway, I really liked this article. It's simple, easy to follow, and reminds me of chemistry class in the good old days of highschool/community college. Voted up and useful :)

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