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A Demonstration of the Pressure
on Santa to Get Down that Chimney
Recommended Grade Level(s):
Appropriate for: Middle school and High school
Time Requirements:
Activity Time: 20 minutes
Teaching Topics & Concepts:
• Students explore atmospheric pressure (high pressure vs. low pressure), partial vacuums, and the behavior of molecules
• How temperature affects the kinetic energy in gases
• Observation skills
Background:
Air pressure, or atmospheric pressure, is a measure of the weight of air in the atmosphere. Air pressure changes with altitude and
different temperatures. When there is low temperature, air pressure is high. This is because cooler air is more dense than warm air.
When there is a high temperature, air pressure is low. Scientists use a barometer to measure air pressure, which meteorologists use
to predict short-term weather changes.
In this experiment, we decrease the pressure in the bottle so that it's no longer equal to the outside air pressure. We reduce the
pressure inside of the bottle by creating a partial vacuum. This scientific principle is indeed the magic behind Santa's ropeless
chimney rappel.
Materials:
• Matches (adult supervision required)
• A shelled hard-boiled egg
• A conical flask or bottle with a neck that is just smaller than the egg (e.g. a milk bottle)
• Cup of water
Procedure:
1. Place the egg into the cup of water
2. Light a few matches (striking matches should be done by an adult)
3. Drop the matches into the jar
4. Quickly place your egg on top of the jar so it completely covers the opening
Watch a Ward's Science video demonstration of this activity here.
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Safety
• Wear lab safety gloves, goggles, and an apron or lab coat.
• Get adult help or supervision when using any sharp objects (such as a knife).
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