Semiconductor

A material that passes electricity well, like copper, is a conductor. One that does not, like rubber, is an insulator. A semiconductor sits between the two, so depending on conditions it lets electricity flow or stops it. It is mostly made from silicon, which comes from sand.

This property is used to make tiny switches that turn electricity on and off, and a chip the size of a fingernail holds billions of them. Chips are divided mainly into memory chips, which store information, and logic chips (non-memory chips), which calculate and make decisions. CPUs and GPUs are logic chips.

Think of a water faucet. A faucet turns water on and off, and a semiconductor lets electricity flow and stops it. Billions of these faucets work together to calculate in 0s and 1s.

Semiconductors go into almost everything that runs on electricity: phones, cars, refrigerators and AI. That is why who makes them and who buys them becomes a major issue between countries.