what is the difference between a politician and a political scientist?

A politician is one who is involved in politics and form government to rule the country. On the other hand a political scientist is one who make a study of politics, its future consequences, study of the government etc. 

A politician is practically involved in the field of politics and deal with the matter of politics. But, a political scientist is specialised in the subject of politics and can make analysis. He does not get involved practically.