Here's a wonderful lesson plan where the teacher makes simulated ice core samples for the students to study:
Frozen in Time: Ice Cores by Jan French
Click here for the Pdf lesson, complete with ice core instructions and student worksheet.
Click here for PBS "Stories in the Ice."
Click here for National Ice Core Laboratory.
Click here for another Pdf lesson in which the students model their own ice cores using play dough and other substances. Then their cores are exchanges and studied. Very kewl!
Click here for a nice "movie" of the life of a snowflake, showing how a glacier forms in layers from snow. Click here for accompanying lesson.