How would you teach Grade 9-12 level Science to students falling behind?

I am taking a year off from work and planning to leave to teach Math and Science in a school of a third world country. It's located in a very bad neighborhood where students find it hard to grasp simple concepts (I have visited before).

My question is: What kind of material can I use for teaching these kids?

Obviously, I have lots of good standard material. But it is very dense for them. I am looking at books that use analogies, good examples.

Can you suggest any resources?

P.S. I'll also be researching and writing year-round. I'll be collating these innovative teaching concepts and compile it into a website so that others can also use it for free.

Thanks