Egg in a Bottle
Emily Jacobs
Materials:
1. shelled hard-boiled eggs (enough for one per student)
2. narrow-mouthed jars (i.e. milk bottles or Starbucks Frappuccino jars)
3. several boxes of matches
4. newspaper (cut into strips)
Estimated Lesson Time:
15-20 minutes
Procedure:
1. Begin by asking for a definition of air pressure. Compile the
various answers and write this on the board. Keep it there throughout
the activity.
2. Place the egg on the bottle to show the students that it will not go into the bottle.
3. Light a strip of newspaper on fire using the matches.
4. Put the burning paper into the bottle.
5. Immediately place the egg on the top of the bottle, putting the small end into the end.
6. Draw the diagram (below) on the board, beginning with just the egg
and the bottle. As you explain the reasoning, add the different
features.
7. Discuss why the egg was "sucked" into the bottle when it was unable to fit before.
Physical Explanation:
Because of the heat from the fire, the air inside
the bottle rushes out. When the egg is placed on the bottle, however,
the fire goes out and the air cools, condensing again. This lowers the
air pressure inside the bottle. Because the air pressure outside the
bottle is greater than that inside, the air pressure outside the bottle
pushes the egg into the bottle.
Citations:
University of Illinois Extension
BJ's MST Science