Spangler Salutes Emily Pringle

Hamilton Middle School was Steve's latest destination.

Hamilton Middle School was Steve's latest destination, as he checked out one of the brightest mad scientists in the Denver Public Schools. Emily Pringle has taught in the Denver Public Schools for eight years and uses the scientific method to make the light bulbs come on in the minds of her bright and eager young students.

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Ms. Pringle and the kids showed us her candle lab experiment, also known as the "composition of air" demonstration.

Here's the concept... A candle sits in the bottom of a dish full of colored water. The candle is lit and covered with a test tube or jar. When the candle burns out (because of the lack of oxygen), the water rises in the test tube. Data is gathered as to the volume of water that displaces the air in the tube.

Ms. Pringle's class concluded from the experiment that 21% of the air that we breathe is oxygen (and the students are correct!). Emily has made quite the impression during her career. We received dozens of emails about the impact she's had on teaching science and opening minds to the wonder of discovery and experimentation.

Composition of Air

Wade Wright - September 15, 2011

This user gave 2/5 stars

It is true that the candle will go out due to the lack of oxygen. However, if one is familiar with the reactants and products of a combustion reaction it is plain to see that while the oxygen did not disappear. It is still there in the form of carbon dioxide and water vapor (note the condensation on the inside of the beaker). For those skeptics, try measuring the volume of water going into the beaker using one candle. Then try using two candles...three candles. You will find that the water goes up higher in the beaker. Does this mean that there is a higher percentage of oxygen in the air when more candles are burned? I think another explaination is needed.