Why is learning by assimilation considered to be so effective.

Learning by assimilation is so effective for it involves a concise and logical approach. Most people who require clear understanding and explanation of ideas, information and abstract concepts must use this approach of learning. The reason is that, they are more attracted to logically sound theories rather than more focus on people approach and based on practical value.  

In assimilating learning, people prefer readings, listening to lectures, exploring analytical models, and having time to think things through on their own. With this, all the important concept and data is clearly inculcated and stored in mind.

found in the nucleus

has mass of one amu