Consider that memory is typically divided into 4 categories: Short Term Memory, Working Memory, Long Term Memory, and MetaMemory.
So, to help kids understand how their memory works, we need to address all 4 types of memory. Take a look at the following pages and see if there are any suggestions you can use with your middle school learners.
Memory Strategies for Long Term Memory
http://www.youtube.com/watch?v=1xeHh5DnCIw&feature=relmfu
Memory and Level of Processing: A College Professor Talks to Students about Study Skills
