Final answer:
The technique for joining copper water pipes is called soldering. Soldering involves melting a filler metal, called solder, and applying it to the joint between two pipes to create a strong and watertight connection.
Step-by-step explanation:
The technique for joining copper water pipes is called soldering. Soldering involves melting a filler metal, called solder, and applying it to the joint between two pipes. The solder then solidifies, creating a strong and watertight connection. This technique is commonly used in plumbing and is an effective method for joining copper pipes