In this paper, we propose Thermoscore, a musical score form-that dynamically alters the temperature of the instrument/player interface. We developed the first version of theThermoscore display by lining Peltier devices on piano keys.The system is controlled by MIDI notes-on messages from anMIDI sequencer, so that a composer can design songs that aresequences of temperature for each piano key. We also discussmethodologies for composing with this system, and suggesttwo approaches. The first is to make desirable keys (or otherkeys) hot. The second one uses chroma-profile, that is, a radarchart representation of the frequency of pitch notations in the-piece. By making keys of the same chroma hot in reverse proportion to the value of the chroma-profile, it is possible to-constrain the performer’s improvisation and to bring the tonality space close to a certain piece.