This is the fourth unit in a series that introduces population concepts into the eighth grade American history curriculum. (See SO 013 782 for an overview of the guide.) In Episode IV, the history topic is union under the Constitution. Objectives are to (1) help the student to examine the need for collecting information on the population during the developing period of a nation; (2) identify the conditions and issues that were the basis for the drafting of Article I, Section 2, of the Constitution; (3) scruntinize the processes of implementing a census in a country; and (4) contrast the Census of 1790 with the Census of 1970 in the United States. In addition to reading and discussing, activities include involving students in administering a census to each other, pretending they are a colonist in 1755 and filling out a census form, role playing the debate concerning the type of government the Constitutional Convention would establish, and role playing legislators in Congress in 1970 with the task of writing a law to implement Article I, Section 2 of the Constitution. (NE)