What term describes the melting under intense heat of two objects or substances, the joining of metals, or the process of heating glazes to ceramics and glass?

• A. Annealing
• B. Fusion
• C. Soldering
• D. Welding

Answer: (B)

Fusion describes melting substances so they flow together and become one piece. When metals are joined by fusion, the pieces melt at the joint and fuse into a single, continuous mass. The same idea applies in ceramics and glass: heating glazes or glass pieces until they melt and fuse to form a seamless surface. This broad sense distinguishes it from welding and soldering, which are specific joining methods—welding involves melting the base metals, while soldering uses a filler metal that melts but leaves the base pieces solid. Annealing is a heat treatment that softens material and relieves stress without melting or fusing pieces. Therefore, fusion best captures the concept of melting and joining across materials like metals and glass or ceramics.