The Office of K-8 Science of American Chemical Society has just released a free middle school science resource. This resource includes activity-based lesson plans for teaching basic chemistry concepts at the middle school level. The lessons cover all the main concepts in middle school chemistry so any part of a lesson, or the entire lesson, can be used on its own or in conjunction with the curriculum the teacher is already using. Each lesson also contains integrated animations and video that a teacher can use to help explain student observations on the molecular level.