Feb 2, 2007
Egg in a Bottle
Ever fancied squeezing an egg into a bottle? No? Well, it’s a kind of perennial physics demonstration that science teachers the world over love to do. I could simply describe how to do it and the results you might expect, but that would be no fun at all. Instead, I spent a good ten minutes scanning videos on the net where individuals attempted to carry out this experiment, some of them more successfully than others. Most handling naked flames and solvents (methylated spirits and the like) in a non-laboratory setting with absolutely no safety equipment (not even goggles) in sight.
More importantly though, most of these experimenters managed to get most of the egg in the bottle, but usually the egg split and simply splurted into the bottle rather than squeezing through the neck and plopping into the bottle intact.
In this video, the “researchers” succeeded in getting a nice squeeze and plop (far better even than the Brainiac team in their attempt).
The key to their success is apparently using a bottle with a nice wide neck. Most of the other videos try to use a beer bottle or something similar which constricts the egg as it squeezes through the opening and splits it.
So, how does it work? What mysterious force is pulling the egg into the bottle? Well, the answer is there is no mystery it is simply air pressure pushing down on the egg. But, wait a minute, what’s the burning paper got to do with air pressure?
Okay, here’s the short of it. Dropping a burning spill (or burning piece of paper into a bottle) and the air in the bottle will quickly expand and a small volume escapes. When the hard-boiled egg (with the shell removed) is placed into the opening, the spill goes out, the remaining gas cools and contracts and the greater outside air pressure pushes the moist flexible egg into the hole nicely.
If you use a nice moist egg and a bottle with a wide enough neck you’ll get a nice squeeze and plop. Anyone who has a use for a hard-boiled egg covered in burnt paper stuck in a bottle is welcome to contact us at Sciencebase with their ideas. Additionally, if you know how to get the egg out again without breaking the bottle leave us you thoughts in the comment form.
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Courtney said,
February 2, 2007 at 10:21 pm
Couldn’t you use another bottle to get the egg out, one with a slightly smaller neck? If you put the first one upside down on top , and then wait till the egg is pulled halfway through, it seems like you should be able to grab it. Alternatively, chop the egg up inside the bottle - it would be ruined, but the bottle would be unbroken!
Hmm said,
February 3, 2007 at 9:09 am
Isn’t it just that the flame heats the gas, causing it to expand. Then when the egg is placed on the bottleneck the chamber becomes sealed, and as the gas is cooled down in the bottle it begins to shrink and that causes a pressure decrease, sucking down the egg.
AmkG said,
February 3, 2007 at 10:51 am
get the egg out again? Sounds like a reverse problem. Get a tripod and suspend the bottle upside down, so that the egg is at the bottom. Then get a fireproof container able to engulf the tripod+bottle, light some paper under the tripod, and cover the thing completely with the fireproof container. I would expect this to work in reverse, but you’ll need even more paper.
David Bradley said,
February 3, 2007 at 11:01 am
Glad you spotted the deliberate mistake! I’ve edited accordingly.
Great idea on how to get it out again.
Karl said,
February 5, 2007 at 8:37 pm
theres a much eaiser way to get teh egg out of the bottle. tip it upside down and blow into the neck. you’ll pump in some air and the egg acts as a valve and the hgiher presure inside pushes it out again Videojug has the vid
http://www.videojug.com/film/how-to-suck-an-egg-into-a-bottle
aurora said,
February 8, 2007 at 2:54 am
im doing that same thing for my science fair do you have any good pics of it for my title page??
David Bradley said,
February 8, 2007 at 10:38 am
There are lots of pictures of this on the web that might be usable in this context without copyright problems. Alternatively, why not simply photograph the experiment as you do it, then you will have your very own photograph for the title page.
Jeff Bailey said,
April 28, 2007 at 8:25 am
My son and I are thinking of how the egg in the bottle experiment
helps give insight into other phenomena in the world. What phenomena
in the world can be explained by the laws of physics which dictate
the egg entering the bottle.
Jeff
David Bradley said,
April 28, 2007 at 8:27 am
Hi Jeff, I emailed you offlist too, but here are a few key phrases to help you seek out more information what is happening physically and chemically in the egg in a bottle experiment:
Thermal expansion and contraction. Pressure gradients. Protein structure and elasticity. Thermal denaturation of proteins that lead to the solidification of albumen. Combustion chemistry. Soot formation. Gases in the atmosphere.
Katie said,
September 26, 2007 at 8:52 pm
No need to worry about tri-pods and flames, simply tip the bottle upside down and heat the air inside with a hair dryer. The egg will “pop” right back out.
David Bradley said,
September 26, 2007 at 10:48 pm
Nice one Katie, I’ll give it a try next time I’ve trapped an egg in a bottle.
db
Emily said,
November 16, 2007 at 2:43 pm
thanks so much for helpin me do this experiment i did this for my science fair project
David Bradley said,
November 16, 2007 at 3:20 pm
Emily, do come back and let us know what grade you achieved…
David Bradley said,
December 17, 2007 at 11:26 am
This post is a perennial favourite on Sciencebase. Has anyone recorded a video better than the one I show here. It would be nice to update the post with something more exciting.
db
eric said,
February 24, 2008 at 6:56 pm
this is not what i was looking for this project is what i am doing but you gave no steps.
yashiko said,
April 12, 2008 at 4:16 am
dat was kool i’m doin dat for my science project kool now how do u get tha egg out!!!!!!!!!!!!
ANN!3 said,
April 15, 2008 at 7:45 pm
I JUX LUV DIZ SCIENCE PROJECT IM THINKIN BOUT DOIN DIZ…ANY MORE OF THESE SCIENCE PROJECT…?WELL JUX TELL ME….
LUV ALWAYZ,
ANN!3
THANKS!!!!!!!!!
David Bradley said,
April 15, 2008 at 7:59 pm
yes ann!3 we’ve got a whole learn with sciencebase page, check it out.
db
Hannah Thompson said,
April 23, 2008 at 4:37 pm
heyyy… i am doing the egg in the bottle 4 a science far thank you 4 your anformation :)
David Bradley said,
April 23, 2008 at 4:51 pm
No problem Hannah, hope it goes well. For more science projects, check out the learn with sciencebase page
db
cheyenne said,
April 29, 2008 at 8:47 pm
well … it ok, 4 science!!!
Amanda said,
May 12, 2008 at 1:35 am
Where do u put the burning paper?How does it spill?What is the material u need to make it spill?
David Bradley said,
May 12, 2008 at 8:29 am
“Spill” is another word for a splinter. Usually, in such an experiment one would use a thin piece of light wood that would be lit and dropped into the bottle.
db