Starting the Seventh Grade year with the study of combustion, during the first chemistry block, is an excellent way to capture the attention of twelve and thirteen year olds. Every Waldorf grade school student is familiar with that homely object, the candle. The sweet smell of melting beeswax, the warm golden glow of the flame, the flowing, twisting, upward curl of the “smoke fairies” rising from beneath the candle snuffer, are an integral part of the sensory experience in a Waldorf classroom. However familiar candles may be, how many students have spent time closely observing a candle flame, and how many can describe the colors and behavior of that flame? What better way to train the powers of observation than by asking students to observe and draw a candle flame, as precisely as possible, with colored pencils. (Objective observation is an antidote for the emotional roller coaster ride of seventh grade.) When we made these drawings, students were surprised to notice that the outer edge and point of the flame is a more radiant orange than the interior yellow, and that the bottom of the flame, closest to the wick, is dark and blue. Beautiful, precise drawings of a candle and its flame became part of the the chemistry main lesson books, along with many other drawings that illustrated the transformation that occurs during the process of combustion.
The seventh grade students observed many objects being burned, some brought from home: steel wool (like a 4th of July sparkler), feathers (peuuw!) a ping bong ball (ignites with a great whoosh, big flame), a small bonfire, metal salts, and many candles. Over time, with careful observation, they discovered lawfulness in the combustion process: smoke moves upward, ash falls downward. Another experiment: Place a different substance on each of the four corners of a metal plate (a lump of sulfur, a tiny piece of magnesium tape, match heads and headless match sticks). Hold a blow torch under the center of the metal plate and observe the order in which each substance ignites, the color of the flame and smoke, and the nature of the ash. A conclusion was developed: a substance must be heated until it reaches its “kindling temperature” in order for it to burn. There were other laws discovered while burning candles under different conditions: Light a candle, invert a jar over it and observe the flame grow smaller and smaller until it winks out and smoke fills the jar. Conclusion: Fire uses up air. Take the same jar that had been inverted over the first candle, and gently lift it and place it over a second lit candle and the flame immediately dies. The “used-up air” remained in the jar. Conclusion: Fire needs air to burn. Without air fire cannot exist. From those experiments the students determined that there are three conditions necessary for a fire to burn: air, fuel (substance to burn), and kindling temperature (spark or fire). Remove any one and the fire cannot burn. The seventh grade students then immersed themselves in the colors of combustion by painting a picture of a lively bonfire.
The arts of speech and poetry also enlivened the study of combustion. Students were asked to recall stories from their study of ancient civilizations in fifth grade, and were given a verse from the Vedas about Agni, the Indian God of Fire, to learn by heart and to illustrate. In sixth grade eurythmy class they had moved to a poem about flint during the mineralogy block. Now they were given the poem to learn, because flint is not just a rock – it “holds fire.” Finally, each student was asked to write a poem about fire. Laughter, applause, and appreciative “ohh’s” filled the room when the poems were read. The seventh graders thinking had been kindled as they learned about the lawfulness of combustion and the great transformation of substance and they had been warmed and touched by the inner transformation that occurs through artistic activity.