To keep control of generally a considered enemy such as the Jews during WWII and the Japanese in the U.S. and Canada. Canada had what they lovingly called "camps" in the Interior of B.C. The people were freezing in the winter and frying in the summer. They were given just the necessities in clothing and food and no more. Even though they were Canadian citizens they were considered the enemy and thus they lost their homes and contents in the homes. Unfair? You bet it was! At least they should have put them into more comfortable lodgings in the camps and kept their homes and contents for them to come back too. Just recently the Canadian Gov't had to pay per Japanese person and their children a $17,000 for this treatment. It did nothing to take the nightmarish trauma away and the loss they incurred.
to scare and kill Jews
There were different types of concentration camps, and the true purpose of some was not hidden. Please see the related question.
Originally, the Nazi concentration camps were used mainly for political oponents of the Nazis.
what was Hitler's purpose for sending Jews to concentration camps and what is a concentration camp.
to torture and eliminate jews
The purpose is to show people how life was like at tose concentration camps, and see what the hardships were, and what they faced. "Those who forget history are doomed to repeat it"
No. Most Jews were unaware of the existence and purpose of the Concentration Camps and the Death Camps.
To concentrate enemies of the state in one place.
There were concentration camps in the Holocaust. The concentration camps were basically work/death camps.
The key disinction is between 'ordinary' concentration camps (such as Dachau or Buchenwald) and extermination camps such as Treblinka and Sobibor. The sole purpose of extermination camps was to kill. Note that Auschwitz and Majdanek combined both kinds of camps.
No there are no more Concentration camps