HEATING—Most one-room schoolhouses had a potbelly stove. The benefit of this type of stove was that it burned many types of fuel—wood, coal, corncobs, straw, and cow chips. Farmers usually provided fuel for the stove. It was the teacher’s responsibility to maintain the fire. Students sitting close to the stove were inevitably too warm and had a hard time staying focused on the lesson as they fought off drowsiness. Students in the corners or by the drafty windows were often cold, and would have to wear many layers of clothing and maybe even a hat. The advent of not only central heating, but also air conditioning has led to many improvement in the learning climate. Teachers now focus on teaching and less on maintaining environmental comfort. Needless to say, students can concentrate better without the distraction of extremes in temperatures. Controlling the physical climate of the classroom has also allowed communities the option of extending the length of the school year in the warmer and colder sections of the country.