Nanowires
Nanowires is tiny threads of material so thin that thousands could fit across a single hair.
Think of it this way
A single strand of angel hair pasta looks thin floating in a bowl of water. But a nanowire is thousands of times thinner still. You could line up thousands of nanowires across just one pasta strand. That is how small these tiny threads of material are.
Explaining nanowires by grade level
Some metals can grow into very thin threads when they get hot. These threads are so small you need a strong tool to see them. Think of a wire thinner than a strand of a web. Heat helps them form and grow longer.