We put a lot of time, energy, and (at times) money into creating new materials for our website. It would be a shame if no one ever used it. So the first part of our usage policy is to say "Please use our stuff." Don't hesitate. Make an Interactive a central part of your lesson plan. Point students in the direction of an Interactive during a class period. Give them a take-home challenge that centers around the use of one of our Interactives.
You'll likely notice the activity sheets that accompany many of our Interactives. Those have been placed on our website for teachers to use as well. If you must, then feel free to print them out, make copies and distribute them to your students. They are placed on our websites to support the work of students, teachers and classrooms. As mentioned, we put time and energy into making them as well. So it would be a shame if no one ever used them.
So if the use part of our policy is to use what we created as often and as extensively as you can, the abuse part of our policy is to ask you to leave what we have on our website. We spent more time creating these Interactives than the time spent creating this year's meals. You would be upset if we took your meals home to indulge ourselves. And we get upset when others take our content and place it elsewhere. Furthermore, we spent almost as much money on the Physics Interactives as the money spent to purchase the cars that sit in our garages. You would be upset if we broke into your car and drove off with it as if it were our own. Similarly, we get upset when others take our content home as if it were their own. Whether its an interactive or a supporting PDF, the bottom line is that the content is to stay on our website. The Physics Classroom isn't going anywhere; you can trust that our content will always be here. Please don't take it and put it elsewhere. Thanks!