An adhesive works by
- A. melting the two surfaces together
- B. forming intermolecular forces or chemical bonds with both surfaces while cohering strongly within itself
- C. removing all air from between the surfaces only
- D. converting one surface into the other
Explanation
A good adhesive must both adhere, sticking to each surface, and cohere, holding together internally, and it usually starts as a liquid so that it can flow into the microscopic irregularities before setting. Failure at the interface is adhesive failure while failure within the glue itself is cohesive failure. Welding, by contrast, does melt the surfaces and is not adhesion.