|
||||||
|
Aluminum is an abundant (2) metal (1), which has many uses (3). It comes from (4) an ore (5) that looks similar to clay (6) called Bauxite. Aluminum is one of several (8) substanes (9) contained in Bauxite. They have to grind the bauxite (11). Next the Bauxite is put (12) into pressurized (13) tanks. In these tanks the other substances form a mass (14), the mass is removed (15) using filters (16). Only a liquid remains (17). It is then put through several other processess (18) until it yeilds a powdery (20) white (21) chemical. (19) This white chemical, Alumina (22), is actual a mixture (23) which contains aluminum (24) and oxygen (25). The Aluminum is then seperated from the oxygen (26) using electricity (27), a metal has been produced (28). This metal is light (29) and is bright (31) silver (32). Aluminum comes in many different forms (33). Missing: IU # 10 "extract these other substances from the bauxite" [Note that this IU is a generalization of the process, the details of which are presented in the following sentences. The student has simply left out the generalization, perhaps feeling that it was redundant.] IU # 30 "has a luster" |
||||||