Understanding the constructive and destructive part of it (mochaik).
Running and Jumping for Enjoyment on Shabbos;
This Melacha Applies to Sifting Wanted or Unwanted Particles. Does the Concept of מיד (Miyad/Immediate Use) Apply to This Melacha?;
plastic containers that are sealed with a adhesive label, plus the containers that have a shrink wrap plastic around it;