Joseph Priestley dephlogisticated air show (ChemEd 2011 session)

Teacher dressed as Joseph Priestly.Dressed as the man himself, Ronald Blatchley performed a series of chemical demonstrations as he shared the life and work of Joseph Priestley with the conference attendees. Ronald begins by asking  “How does one present chemistry to the general public in a positive light?” While he never directly answered the question, he did indicate that the combined use of history and chemical demonstrations has proven to be successful for himself and the other volunteers working at The Joseph Priestley House in Northumberland PA.

Ronald performed the copper-into-gold (brass) conversion demonstration as he related how alchemy was still practiced during the time of Joseph Priestley. The different airs — fixed (carbon dioxide), inflammable (hydrogen), and dephlogisticated (oxygen) — were generated and tested with a burning or glowing wooden splint as Ronald discussed the contributions of Joseph Black and Henry Cavendish, as well as noted Priestley’s own discovery of oxygen. Ronald also showed how a sunflower seed or piece of steel wool burns more rapidly in the presence of dephlogisticated air. Ronald ended the presentation with a bang — igniting a bottle filled with a mixture of two parts inflammable air and one part dephlogisticated air.

Ronald’s presentation was entertaining and very informative, in terms of both Priestley’s contributions to science and his life in general. A more realistic image of the man as a human being who was interested in science was created in my mind, and I’m certain in the minds of others in attendance as well. Those of you interested in the Joseph Priestley House can find more information on their website.