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.
How long does it take to become a psychologist? The time it takes to become a psychologist depends largely on your specialty area and career interest. But here is a general timeline. The Path to Becoming a Psychologist. First, you will need a bachelor's degree (4 to 5 years), which teaches the fundamentals of psychology. After that, you will need a master's degree (2 to 3 years), which can qualify you to practice in the field as a case manager, employment specialist, or social worker. Then, most state licensing boards require a doctorate (4 to 7 years).