Reading Selection, Lessson 6
The Properties of Asbestos: The Pros and ConsClick here for audio and Spanish translation
Many substances burn when they are heated. Others melt or evaporate. Some substances, such as asbestos, do not change when they are heated. This property can be very useful. For centuries, people have known that this fibrous mineral has many useful properties. It is fire resistant. It does not melt or react with air, at least not until it gets very hot. One form of the mineral withstands temperatures up to 2750 °C. It is a very good insulator. It is strong. It resists acid. It is chemically inactive. It can be woven into cloth. Asbestos has some very useful properties, and it is readily available at a low cost.
The Romans used asbestos for lamp wicks. Egyptians used it to make burial cloths. In modern times, asbestos has been used in roofing and flooring, electrical and heat insulation, and brake linings. Because of its fire-resistant properties, asbestos has been used for a wide variety of other purposes, from theater curtains to firefighters' suits and gloves.
Many substances with useful properties have some undesirable ones as well. (Although the amount of the substance involved is an important factor.) Use library and Internet resources to answer the following question: What are some properties and some of the pros and cons of using one of the following substances: mercury, plutonium, or benzene?