<human>:  How does the material called ‘Liquid Crystal’ work?
<bot>: Liquid crystals are a type of material that can be in two states at the same time. They are called liquid crystals because they are liquid at room temperature. They are used in LCD screens, and in some types of watches. They are made up of molecules that are shaped like rods, and they can be arranged in different ways. When the molecules are arranged in a certain way, they can block light from passing through them. This is called a “twisted nematic” state. When the molecules are arranged in a different way, they allow light to pass through them. This is called a “homeotropic” state.