ELI5: Explain Like I'm 5

Polycrystalline silicon

Polycrystalline silicon is made up of tiny crystals that are all connected together. It is a type of material that is used to make things like solar panels and computer chips. It is strong and can conduct electricity, which makes it useful for lots of things. Polycrystalline silicon is created by combining different types of sand and using heat and pressure to make all the small crystals join together.