scenes not changing in unity when my guy hits the collider

  1. use code tags:
    Using code tags properly

  2. do you get any errors in the console when you intersect the box? Note that if you haven’t included the scene you want to load into the build list, then it won’t be able to. You’ll see a red warning message in the console complaining about this when you call load if this is so.

  3. another possibility is that one of your entities doesn’t have a Rigidbody attached (or charactercontroller). See the matrix at the bottom of this page to see what needs to be setup to receive the appropriate messages:
    Unity - Manual: Introduction to collision