Mendeleev.com
What is inside a USB cable?
A USB cable looks simple from the outside, but inside it must carry power and high-speed electrical signals while surviving repeated bending.
Copper is the usual conductor because it combines high electrical conductivity with good ductility. Different wires inside the cable carry power and data, with geometry chosen to control electrical behaviour.
Insulating polymers keep conductors separated. Data pairs are often twisted, and shielding made from metal foil or braid can reduce electromagnetic interference.
The connector adds plated metal contacts and a mechanical shell. Gold may appear as a very thin contact finish in some designs because it resists corrosion, but the bulk conductor is not gold.
Why this object uses several materials
Most manufactured objects solve several problems at once: strength, electrical conduction, thermal behaviour, corrosion resistance, weight, appearance and cost. One pure material rarely satisfies all of them.
That is why a useful way to read an object is part by part. Each component reveals a different compromise between chemistry, physics and engineering.
What changes in practice
Real examples often add one more layer: geometry, impurities, coatings, humidity, flow or manufacturing history can alter what you observe even when the main mechanism is unchanged.
That is why two objects made from broadly similar materials can behave differently. The useful question is not only “what is it made of?” but also “how is it built, under what conditions, and for which function?”