Thus by 1803 there were two known rare earth elements, yttrium and cerium, although it took another 30 years for researchers to determine that other elements were contained in the two ores ceria and yttria (the similarity of the rare earth metals' chemical properties made their separation difficult).
For instance, students who pursue a Ph.D. in psychology usually take from five to seven years depending upon required coursework as well as internship and supervised residency requirements.
Obtaining a PhD in psychology usually requires 5 to 7 years of graduate study after the bachelor's degree is received. Usually, a dissertation is required, but a PsyD degree can be based on practical work experience and exams instead.iper1 I just finished my Bachelor's in Psychology. It actually takes anywhere from 180-195 credits, and does take four years if you are taking 2 classes a semester. If you take on a heavier class load, it is possible to graduate in 3 years.