The actual structure will always differ somewhat from these idealized forms, as the differences in energy between the conformations are small compared to the thermal energy of the molecules: Alkane molecules have no fixed structural form, whatever the models may suggest.
ðɪ ˈæktʃuːəl stɹˈʌktʃɚ wɪl ˈɔːlweɪz dˈɪfɚ sˈʌmwʌt fɹʌm ðiːz aɪdˈiəlaɪzd fˈɔːɹmz, æz ðə dˈɪfɹənsᵻz ɪn ˈɛnɚdʒi bᵻtwˌiːn ðə kɑːnfoːɹmˈeɪʃənz ɑːɹ smˈɔːl kəmpˈɛɹd tə ðə θˈɜːməl ˈɛnɚdʒi ʌvðə mˈɑːlɪkjˌuːlz: ˈælkeɪn mˈɑːlɪkjˌuːlz hæv nˈoʊ fˈɪkst stɹˈʌktʃɚɹəl fˈɔːɹm, wʌtˈɛvɚ ðə mˈɑːdəlz mˈeɪ sədʒˈɛst.