The  basic question...
How to hold materials together ?
nails.tif
Substrate.tif
Substrate.tif
Adhesive – substance  capable of holding  materials together by
• Adhesives...perhaps the first technology  • Adhesion/cohesion
8.1.0
Substrate.tif
Substrate
Substrate.tif
Substrate
Substrate
Substrate
Compare the benefits  of adhesives to  mechanical fasteners
adhesive.tif
Adhesive