Corrugated cardboard has two main components: the linerboard and the medium. Both are made of a special kind of heavy paper. Linerboard is the flat facing that adheres to the medium. The medium is the wavy fluted paper in between the liners. Single Wall is manufactured with the medium between two sheets of linerboard. Double Wall has three sheets of linerboard with two mediums in between.
A new Microsoft-commissioned survey shows European girls lose interest in STEM subjects around the age of 15. Microsoft admitted it doesn't have a comprehensive explanation for why 15-year-old girls lose interest in science and math.
This is to allow the subject to be studied without any of the maths which might be first studied by the A-level maths group at the ages of 17 and 18. Thus physics at school has become considerably more descriptive and visual than it was 20 years ago. The same applies to a lesser extent to chemistry.