Table of Contents: 1  INTRODUCTION, DEFINITION & VALUE OF RESEARCH. 2  SCIENTIFIC METHOD OF RESEARCH & ITS SPECIAL FEATURES. 3  CLASSIFICATION OF RESEARCH:Goals of Exploratory Research. 4  THEORY AND RESEARCH:Concepts, Propositions, Role of Theory. 5  CONCEPTS:Concepts are an Abstraction of Reality, Sources of Concepts.
Lead poisoning is a serious and sometimes fatal condition. It occurs when lead builds up in the body. Lead is a highly toxic metal and a very strong poison. It is found in lead-based paints, including paint on the walls of old houses and toys.
History and Uses: Lead has been known since ancient times. It is sometimes found free in nature, but is usually obtained from the ores galena (PbS), anglesite (PbSO4), cerussite (PbCO3) and minum (Pb3O4). Although lead makes up only about 0.0013% of the earth's crust, it is not considered to be a rare element since it is easily mined and refined. Most lead is obtained by roasting galena in hot air, although nearly one third of the lead used in the United States is obtained through recycling efforts.