Life Science Curriculum 8-12
Submitted by: James E.S. Wiseman
Institution: Azusa Pacific University
Title of Experiment: The Amazing, Egg-Gobbling Bottle
1 peeled hard-boiled egg
1 book of matches
1 glass bottle (egg should fit snugly in mouth of bottle without falling through)
Scientific Background of Experiment:
The advantage of this experiment is that is can be used to demonstrate two separate concepts. The first is the necessity of oxygen in combustion reactions, and the second is that of atmospheric pressure.
Prior to the demonstration the students observe a rather unexciting set of conditions. Set out before the demonstrator are three objects: a glass bottle, a book of matches, and a peeled hard-boiled egg. The match is lit, dropped in the bottle, and the egg is allowed to sit on the mouth of the container. Surprisingly, (provided that the students don't fully understand how fire works at this point!) the match goes out. Then suddenly, to the astonishment of all, the egg drops through the bottle with a loud POP! The amazing egg-gobbling bottle has done it again.
The principles governing this experiment are constantly informing almost all aspects of our life. We use fire to cook our food, drive our cars, even heat the water that we take a shower with. Atmospheric pressure has an equally expansive influence on our everyday lives. This experiment is a fun exhibition of the effects of both of these concepts.
The air that surrounds us, the invisible gases that we breathe and form our
atmosphere, is a mixture of several elements existing in the gaseous state. 78% of the homosphere (the regions of the atmosphere closest to us) is elemental Nitrogen gas (N2), 21% is elemental Oxygen gas (O2) and about 1% is a mixture of various other gases (Silberberg, 1996). Important for this experiment is the 21% of the homosphere that is elemental oxygen. Not only is oxygen essential as the gas breathed by most living organisms, it is also necessary for the very important function of causing fires to burn.
After the lit match is placed in the bottle and the opening covered, the combustion reaction taking place quickly consumes all of the oxygen in the bottle, converting it to carbon dioxide. Having exhausted its fuel source, the combustion reaction will stop (the flame will go out), leaving only the non-oxygen components of the air and the new carbon dioxide gas in the bottle. Since this newly-formed gas is 'heavier' than the rest of the air, it will settle to the bottom of the container, creating a region at the top of the bottle where the pressure exerted upward has been lowered as a result.
While the pressure within the bottle has now been decreased, that which was originally outside the bottle has remained unchanged and a net force is established pushing down on the egg. Due to the elasticity of the surface of the egg tissue, the sides collapse enough to allow the object to slide easily past the glass walls of the bottle mouth and into the bottom of the container.
1. Strike a match using the book of matches already obtained.
2. Making certain that the bottle is dry, quickly drop the match through the mouth.
3. Quickly place the peeled egg over the mouth, being absolutely sure that the egg is snug enough to seal the opening, but small enough to go through it without a great deal of distortion.
4. Once the demonstration is complete the egg can be removed by turning the bottle upside-down (allow the match to drop out) and, with the bottle inverted, blowing a large amount of air past the egg into the bottle. Quickly move your head, and get ready for the egg to come shooting out.
Misc. Helpful Information/ Hints/ Suggestions:
Be certain to use matches that are on the longer end of the match-size spectrum. This will ensure that the match burns long enough to consume most of the oxygen contained in the bottle after the egg is placed over the opening. Also, it is extremely important that the bottom of the bottle is liquid-free. Not only will the presence of hydrated materials make it frustratingly difficult to keep the match lit, it also makes the process of egg-removal rather messy. Similarly, when removing the egg, don't underestimate the amount of air that must be orally-injected into the bottle before it will pop out. The air you provide must not only compensate for the force of the atmospheric pressure, but must actually exceed this force to push the egg through the hole.