Final answer:
Two types of electrical wiring popular in homes built in the 1960s and 1970s were aluminum wiring and knob and tube wiring.
Step-by-step explanation:
In the 1960s and 1970s, two types of electrical wiring that were popular in homes were aluminum wiring and knob and tube wiring.
Aluminum wiring: Aluminum wiring was used as a cheaper alternative to copper wiring. It was commonly used during the 1960s and 1970s in residential construction. However, it has been found to be a fire hazard due to its tendency to overheat and become loose at connections over time.
Knob and tube wiring: Knob and tube wiring was commonly used in homes built before the 1940s, but it was also found in some homes built in the 1960s and 1970s. This type of wiring consists of individual copper conductors enclosed in porcelain tubes and supported by ceramic knobs. It is considered outdated and is not used in modern construction due to its lack of grounding and insulation.