ðˈʌs, ɐ ʃˈɔːɹt pˈæθ bᵻtwˌiːn ðə hˈɑːt sˈɜːfɪs ænd ðə kˈoʊld sˈɜːfɪs ɪz nˈɛsᵻsɚɹi, tˈɪpɪkli baɪ səspˈɛndɪŋ ɐ hˈɑːt plˈeɪt kˈʌvɚd wɪð ɐ fˈɪlm ʌv fˈiːd nˈɛkst tʊ ɐ kˈoʊld plˈeɪt wɪð ɐ lˈaɪn ʌv sˈaɪt ɪn bᵻtwˈiːn.
Thus, a short path between the hot surface and the cold surface is necessary, typically by suspending a hot plate covered with a film of feed next to a cold plate with a line of sight in between.