Some embodiments include memory constructions having a film of phase change material between first and second materials; with the entirety of film having a thickness of less than or equal to about 10 nanometers. The memory constructions are configured to transit from one memory state having a first phase of the phase change material to a second memory state having a second phase of the phase change material, and are configured so that an entirety of the phase change material film changes from the first phase to the second phase in transitioning from the first memory state to the second memory state. In some embodiments, at least one of the first and second materials may be carbon, W, TiN, TaN or TiAlN. In some embodiments, at least one of the first and second materials may be part of a structure having bands of two or more different compositions.