In the Classroom

Science Discipline(s) Chemistry   Topics Air pressure Combustion   Activity Title Egg in a Bottle Demonstration   Materials
  • Hard-boiled egg
  • Glass bottle with an opening that the egg will not slip into
  • Matches
  • Cotton balls
  • Rubbing alcohol or ethanol
  • 2 100 mL beaker
  • Vinegar
  • Baking soda
  • Pie plate
  • Hair dryer (optional)
  Procedure Preparation
  • Pour rubbing alcohol or ethanol into a beaker
  • Pour vinegar into a beaker
  • Boil eggs and peel hardboiled eggs
  How to get the egg into the bottle
  1. Place egg on the opening of the bottle
  2. Take a cotton ball and soak in alcohol or ethanol
  3. Light a match to light the cotton ball on fire
  4. Remove the egg from the bottle and drop the lit cotton ball into the bottle
  5. Quickly place the egg on top of the bottle
  6. Observe the egg being pulled inside the bottle
  How to get the egg out of the bottle
  1. Tip the bottle with the egg in it so that the egg lays near the opening of the bottle (try to aim the egg pointing straight towards the opening of the bottle)
  2. Put baking soda all around the egg, especially on the sides
  3. Pour in vinegar and quickly flip the bottle upside down with the egg closing the opening above the pie plate
Alternative: Use a hair dryer to heat the bottle while holding the bottle upside down   Links: https://www.youtube.com/watch?v=28TIyWdfxxc https://www.youtube.com/watch?v=ysh2mVMonM8 Questions
  • What is air pressure?
  • How do you think the egg is going to get into the bottle?
  • What happens to the air pressure when air is heated?
  • How is the reaction between baking soda and vinegar get the egg out of the bottle?
  Explanation The pressure outside and inside the bottle is equal. Burning the alcohol soaked cotton ball heats up and expands the air inside forcing the air out of the bottle. Placing the egg on top of the bottle creates a seal, extinguishes the flame due to lack of oxygen, and the air inside the bottle cools. The cooler air molecules move slower, create less collision between molecules, and results in a lower air pressure. The air outside is pushing down on the egg making the air outside and inside unbalanced. Due to the higher pressure outside the bottle, the egg to be pulled inside the bottle. To get the egg out of the bottle, there has to be higher pressure inside the bottle to push the egg out. This can be done by the reaction between baking soda and vinegar. The pressure of the carbon dioxide gas created by the reaction pushes the egg out of the bottle because of the gas molecules moving more rapidly and colliding with each other increasing the air pressure inside the bottle. Alternatively, we can use heat to push the egg out again. If we turn the container upside down and heat the container with the egg inside with a hair dryer or flame, the gas inside the container heats up and creates a pressure inside the container that can push the egg out again. Combustion: alcohol + oxygen —–> carbon dioxide + water C2H5OH + O2 —-> CO2 + H2O + heat   baking soda + vinegar ——-> carbon dioxide + sodium acetate + water Na(HCO3) + H(C2H3O2)—–> CO2 + Na(C2H3O2) +H2O   Next Generation Science Standards This activity can be demonstrated at the 4 – 6 and middle school grade levels. From this fun and simple science experiment, students will learn about air pressure and combustion reactions. An alternative activity that can demonstrate pressure and a combustion reaction is a bottle rocket. A bottle rocket powered by the carbon dioxide gas produced from a baking soda and vinegar reaction can result in the expansion of gas inside the bottle causing it to fly. The NGSS standards that pertain to this activity are and 5-PS1-4, mixing two or more substances can create a new substance with different properties, and MS-PS1-4, develop a model that predicts and describes changes in particle motion, temperature, and state of a pure substance when thermal energy is added or removed.