Description

Ever tried to burn a candle in an inverted jar partially
filled with water?
It’s not the easiest or most accurate way to quantify
the amount of O2 in air. So we came up with a better
way, one that is easy to set up, run, measure, and can
be performed several times in a single class period.
The key is a Mohr’s pinchcock, which helps you gauge
when the pressure inside the flask equals the pressure
outside the flask once your combustion reaction has
taken place. We think this demo is truly a breath of
fresh air! Developed by Lisa Water. Grades 10-12.
Includes:
alcohol, graduated cylinder, cotton balls, Mohr’s
pinchcock, flask with stopper, tubing, and complete
instructions. A ring stand and support ring with clamp
are required but not included.