Egg in a Bottle
The egg in a bottle is a cool science fair idea. Other than providing an insight into the fundamentals of Physics, it makes for a thrilling trick too. However, since it deals with fire, adult supervision is a must for the project.
Egg in a Bottle Experiment
An egg sitting at the mouth of bottle having a piece of burning paper at its bottom gets sucked into its interiors after some time.
- An egg
- Wide-mouthed glass bottle (The diameter of its mouth should be slightly smaller than that of the egg)
- Vegetable oil
- A piece of paper folded lengthwise a couple of times to make a narrow strip
- Place the egg in the saucepan and cover with water by about an inch. Put it to boil for 5 minutes.
- Remove the pan from the heat and keep it covered for 25 minutes.
- Take out the egg and put it in cold water.
- With a paper towel, grease the inner rim of the bottle with oil for lubrication.
- After peeling the egg, place it atop the mouth of the bottle with its narrow end facing downwards.
- With a match, light one end of the strip of paper. Lifting the egg a little, drop the paper into the bottle. Quickly put the egg back into its position.
Ideally, the egg should wriggle a little before getting sucked into the bottle.
How to Suck an Egg into a Bottle: Video
Explanation of the Trick
As the paper strip continues to burn, the air inside the bottle gets heated up, causing it to expand and leave the bottle. The egg begins to wriggle as air escapes from its sides. After consuming all the oxygen within the container, the flame goes out causing the gas to cool and contract. A partial vacuum is thus created inside the bottle, due to the reduction in air pressure. The air outside then tries to get into the bottle to fill up the vacuum, thereby forcing the egg to get sucked inside. In this connection, it may be mentioned that hard boiling an egg increases its intermolecular spaces causing it to become quite flexible, making the experiment possible.
To get the egg out of the bottle, make it block the mouth with its pointed end outwards. Hold the container upside down. Now tilt it a little and blow air into it to increase the pressure inside before tilting it back to seal its mouth with the egg again, which should now pop out.
In case you do not want the fire, you can replace it by pouring hot water into the bottle. You need to be careful about choosing a thin walled glass bottle for this alternative as the thick-walled varieties are prone to get cracked in the process. Teaching the concept behind this experiment should quench the thirst of inquisitive young minds after demonstrating this activity in the lab.