The conduction band is a range of energy levels in a solid where electrons can move freely, allowing them to conduct electricity. In materials like metals, the conduction band overlaps with the valence band, enabling easy electron flow. In insulators, the conduction band is separated from the valence band by a large energy gap, making it difficult for electrons to move. In semiconductors, such as silicon, the conduction band is separated from the valence band by a smaller energy gap. This allows some electrons to jump into the conduction band when energy is supplied, enabling controlled electrical conductivity.