Experiment: Make Binding Forces Visible- Molecular Binding Forces, Recycling/Reuse, Life Cycle Engineering (LCE)

A very simple experiment shows students the difference between primary and secondary molecular binding forces. Use an empty plastic cup for milk, yoghurt or coffee and destroy it by pressing the cup together. You will watch cracks only longitudinal the cup. Try to break the cup horizontally you will fail. What you observe are the secondary binding forces between the molecules oriented along the length of the cup versus the primary binding forces perpendicular to the long side of cup.