School Bag Weight

Matt Bottrell has written about some issues related to the acceptable weight of laptops for school use [1]. Matt cites a reference from the Victorian government stating that a school bag should not be heavier than 10% of the body weight of the child who carries it [2]. So the next thing we need to do is to calculate what a student can carry without being at risk of spinal injuries. Firstly we need to determine what children weigh, if we restrict this to the 14+ age range (the older children h