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.
Popularity: 96. How long does it take to earn a master's degree in psychology? Answer If you are talking about a Masters in Counseling, this could be anything from 1 and a half to about 3 years, depending on wether you are working a full time job at the time. It took me 2 years and a semester, without working full time.opularity: 96. How long does it take to earn a master's degree in psychology? Answer If you are talking about a Masters in Counseling, this could be anything from 1 and a half to about 3 years, depending on wether you are working a full time job at the time. It took me 2 years and a semester, without working full time.