in order to effectively sear,do not pre heat the pan before adding food

Question

 It has to do with sear and you have to find about stuff about searing 

Answer 1

This all depends on what you are looking to sear and the process you are using.

The new school of thought is that you can start a steak in a cold pan and then set your burner up to high heat then flip every 2 minutes. You do this till you start getting a good color on the steak then you drop the temp to medium continue to flip every two minutes. This process allows you to gently warm the steak and get a nice all through doneness without the thick bands of gray overcooked outside.

Duck breasts also work very well starting with a cold pan. I make some cross hatch slits in the fatty skin, then place them in a cold pan and bring the heat up to high. This allows the fat to render out and produce duplicatable and crispy duck skin with perfect medium rare meat. Also allows you to save all that lovely duck fat to make fried potatoes!

If you are using sous vide to finish your meats then you must have a screaming hot pan because you do not want to cook the meat any more, you just want to sear the outside.