How the printing press works would be an excellent topic for students studying machines. Large newspapers may have a science or environmental reporter. Pharmacists Pharmacists and pharmacies are an excellent source of information on chemicals. Photographers A photographer is a natural resource for chemistry. Photographers can also explain how a camera works and make comparisons between a camera and the eye of mammals.
Railroad commission Look in state offices section of the phone book.
This office might have useful information on global position instruments. Soil conservation Soil conservation is usually listed with other government agencies or with US Agriculture. These conservationists often provide numerous teaching aids and most have county soil maps available. Stores Store displays are changed frequently. Many of the mechanical displays are discarded.