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Anne Marie Helmenstine, Ph.D.

Egg in a Bottle Demonstration

By February 10, 2013

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The egg in a bottle demonstration is an easy chemistry or physics demonstration you can do at home or in the lab. You set an egg on top of a bottle (as pictured). You change the temperature of the air inside the container either by dropping a piece of burning paper into the bottle or by directly heating/cooling the bottle. Air pushes the egg into the bottle.

Egg in a Bottle Materials

  • peeled hard-boiled egg (or soft-boiled, if a yolk mess interests you)
  • flask or jar with opening slightly smaller than the diameter of the egg
  • paper/lighter or very hot water or very cold liquid
In a chemistry lab, this demonstration is most commonly performed using a 250-ml flask and a medium or large egg. If you are trying this demonstration at home, you can use a glass apple juice bottle. I used a Sobe™ soft drink bottle. If you use too large of an egg, it will get sucked into the bottle, but stuck (resulting in a gooey mess if the egg was soft-boiled). I recommend a medium egg for the Sobe™ bottle. An extra-large egg gets wedged in the bottle.

Perform the Demonstration
  • Method 1: Set a piece of paper on fire and drop it into the bottle. Set the egg on top of the bottle (small side pointed downward). When the flame goes out, the egg will get pushed into the bottle.
  • Method 2: Set the egg on the bottle. Run the bottle under very hot tap water. Warmed air will escape around the egg. Set the bottle on the counter. As it cools, the egg will be pushed into the bottle.
  • Method 3: Set the egg on the bottle. Immerse the bottle in a very cold liquid. I have heard of this being done using liquid nitrogen, but that sounds dangerous (could shatter the glass). I recommend trying ice water. The egg is pushed in as the air inside the bottle is chilled.
How It Works
If you just set the egg on the bottle, its diameter is too large for it to slip inside. The pressure of the air inside and outside of the bottle is the same, so the only force that would cause the egg to enter the bottle is gravity. Gravity isn't sufficient to pull the egg inside the bottle.

When you change the temperature of the air inside the bottle, you change the pressure of the air inside the bottle. If you have a constant volume of air and heat it, the pressure of the air increases. If you cool the air, the pressure decreases. If you can lower the pressure inside the bottle enough, the air pressure outside the bottle will push the egg into the container.

It's easy to see how the pressure changes when you chill the bottle, but why is the egg pushed into the bottle when heat is applied? When you drop burning paper into the bottle, the paper will burn until the oxygen is consumed (or the paper is consumed, whichever comes first). Combustion heats the air in the bottle, increasing the air pressure. The heated air pushes the egg out of the way, making it appear to jump on the mouth of the bottle. As the air cools, the egg settles down and seals the mouth of the bottle. Now there is less air in the bottle than when you started, so it exerts less pressure. When the temperature inside and outside the bottle is the same, there is enough positive pressure outside the bottle to push the egg inside.

Heating the bottle produces the same result (and may be easier to do if you can't keep the paper burning long enough to put the egg on the bottle). The bottle and the air are heated. Hot air escapes from the bottle until the pressure both inside and outside the bottle is the same. As the bottle and air inside continue to cool, a pressure gradient builds, so the egg is pushed into the bottle.

How to Get the Egg Out
You can get the egg out by increasing the pressure inside the bottle so that it is higher than the pressure of the air outside of the bottle. Roll the egg around so it is situated with the small end resting in the mouth of the bottle. Tilt the bottle just enough so you can blow air inside the bottle. Roll the egg over the opening before you take your mouth away. Hold the bottle upside down and watch the egg 'fall' out of the bottle. Alternatively, you can apply negative pressure to the bottle by sucking the air out, but then you risk choking on an egg, so that's not a good plan.

Watch a video of the egg in a bottle project.

How to Prepare Gases | Major Chemistry Laws
Image: The egg in a bottle demonstation illustrates concepts of pressure and volume. (Anne Helmenstine)

Comments

February 18, 2008 at 8:08 am
(1) Denise says:

I remember first learning about this in Grade 5 in Canada in the very early 1960s! I loved it then, and do it with my own classes now that I am a teacher!

November 17, 2011 at 9:43 am
(2) the person behind oyu says:

Cool! Nice to see you reliveing memories

February 20, 2008 at 7:30 am
(3) Steve says:

Its an old trick, but heres another thing…. Instead of using a peeled boiled egg, take a whole egg and soak it in vinegar for about 6 to 24 hours (depending on what type of vinegar it is).

This makes the shell go very soft.

Then use the flame in the bottle method and the egg, with the intact shell, will slide in to the bottle.

But the good part is that the shell will re-solidify after about 3 days which always makes people think how did you get it in there to start with!

December 4, 2008 at 8:03 pm
(4) brihanna says:

what can you tell me about the the egg in the bottle for my scince project thx cant wate to hear from u

February 2, 2009 at 12:20 pm
(5) Sarah says:

This is sooooooo cooool

March 8, 2011 at 6:30 pm
(6) susu says:

its nasty though

April 25, 2011 at 4:29 pm
(7) chris says:

not really it weard

February 10, 2009 at 9:24 pm
(8) jay solanki says:

wow this was not as fun as i excpected

September 17, 2009 at 8:54 am
(9) daryll says:

ok i knew that this is hard but it is so very easy and i got a highest grades thank you for that wonderful tricks i’ve enjoy hahahahah…..

January 11, 2010 at 5:27 pm
(10) Brianna says:

This is awesome. I am doing a science fair progect and this has helped a lot. Thank-you, thank-you, thank-you!

February 5, 2010 at 3:08 pm
(11) melinda says:

omg thanks u helped me with a science project i did need help with
thank u thank u

May 3, 2010 at 1:44 pm
(12) ikeda says:

i liked dis project…

August 24, 2011 at 7:52 pm
(13) denisse says:

wurrdd it was mad cool lml<3

May 7, 2010 at 7:17 pm
(14) bob says:

i want to see the egg in like in the bottle

August 9, 2010 at 8:11 pm
(15) harpy says:

awesoooome , i remember so vividly, this expression i said is the same way that I’ve showed when i first exhibit the trick during my grade 3.

November 29, 2010 at 6:28 am
(16) kshitiz says:

a good experiment for chem…

January 16, 2011 at 8:52 am
(17) Akiva says:

I need a bar graph of The Project Egg in a Bottle .

February 3, 2011 at 1:49 pm
(18) TWSharpless says:

Here’s something that can go wrong. I did a dry run that worked fine. But 15 mins later before an audience, the egg moved only about 1/4″ into the bottle. I believe the cause was that I neglected to refreshen the air in the bottle. There was too little oxygen to support a flame long enough to heat the air in the bottle.

February 15, 2011 at 2:49 pm
(19) WIRRIAM says:

LOL ROFL THIS EXPERIMENT IS AWESOME ROFL LOL

March 2, 2011 at 1:00 pm
(20) alyssa says:

so f’in cool

October 9, 2011 at 5:43 pm
(21) Lacey says:

Wow! I recommend this to everyone! It’s really cool. Parents will never believe there”s such thing as a egg in a bottle:) ROFL!!!(:

October 30, 2011 at 12:15 am
(22) elvira says:

..wow…………great……its amazing……..tnx for helping me on my project…………….

January 18, 2012 at 9:15 am
(23) riya says:

it did helped me a lot Thank you

January 23, 2012 at 10:23 am
(24) ash ahmed says:

good experiment for small children….

February 8, 2012 at 6:24 pm
(25) zarreah says:

wat i can tell u is that it is a alot of work to do so really just take ur time n do ur best

April 2, 2012 at 10:14 am
(26) tshering chokey says:

ohhh ur experiment is sooo gud it realy helped me thank QQQQQ

November 17, 2012 at 10:22 am
(27) vaishnavi says:

it is so nice experiment it helped me a lot

December 20, 2012 at 4:40 pm
(28) aija says:

i heard it is great

February 11, 2013 at 9:23 pm
(29) ashley says:

omg i like the mt.dew project better nd i won the science fair so coool but this cool to

March 19, 2013 at 8:59 pm
(30) Kameron says:

This is so awesome

December 31, 2013 at 10:53 pm
(31) grande says:

sooooo this project is good & half of the children leaving comments CANNOT spell . good day .

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