The “egg in bottle” science project is a popular and entertaining way to demonstrate basic scientific principles learned in class. This experiment shows how differences in pressure create a vacuum, with mind-boggling results. There are a few different ways to perform it and some key concepts to learn from this experiment.
Basic Egg in Bottle Experiment
The egg in bottle experiment requires use of a hard-boiled egg. Pick off the egg shell before beginning the experiment. You should choose an egg that is slightly too large for the opening of the bottle, or choose another bottle that has an opening slightly too small for the egg you have. Use your fingers to smear some water around the opening of the bottle. Light and drop a match in the bottle and immediately place the egg over the opening, being sure to completely cover the opening. Watch as the egg begins to wiggle around the opening, the match goes out, and the egg is sucked into the bottle.
Removing the Egg
For quick removal, use a straw, fork, or other long object to break up the egg and drain it out. For a more scientific removal of the egg from the bottle, use this technique to remove the egg intact. Turn the bottle upside-down so that the egg rests against the bottle neck. Put your mouth to the opening and blow as hard as you can. This increased the pressure inside the bottle so that the egg can escape. Take your face away from the bottle quickly and catch the egg as it pops out.
You can also do this experiment with a balloon instead of an egg. To perform this variation, fill a balloon with water until it is slightly larger than the opening of the bottle you’re using. Use your fingers to wet the opening of the bottle and repeat the basic experiment with the balloon instead of the egg. Another variation involves repeating the egg experiment with the bottle upside down. Insert two birthday candles into the narrower end of the egg, light the candles, and hold the bottle a few inches above the egg. Hold the bottle there for a few seconds to allow the candles to heat up the air inside the bottle, and then lower the bottle so the edges touch the egg. Watch the candles go out and the egg get sucked up into the bottle.
The key concepts demonstrated by the egg in bottle project involve vacuums and pressure. The egg held against the bottle opening prevents outside, higher pressure air from entering the bottle, while the lit match inside the bottle causes the lower pressure air inside the bottle to contract. The difference in pressure creates a small vacuum, which allows the egg to fall through the opening into the bottle.