The melting point of a substance is the point where it changes state from solid to liquid while the boiling point of a substance (in liquid state) is the point where the vapour pressure of the liquid equals the environmental pressure surrounding the liquid and all the liquid changes state to gas.
ðə mˈɛltɪŋ pˈɔɪnt əvə sˈʌbstəns ɪz ðə pˈɔɪnt wˌɛɹ ɪt tʃˈeɪndʒᵻz stˈeɪt fɹʌm sˈɑːlɪd tə lˈɪkwɪd wˌaɪl ðə bˈɔɪlɪŋ pˈɔɪnt əvə sˈʌbstəns ɪn lˈɪkwɪd stˈeɪt ɪz ðə pˈɔɪnt wˌɛɹ ðə vˈeɪpɚ pɹˈɛʃɚɹ ʌvðə lˈɪkwɪd ˈiːkwəlz ðɪ ɛnvˌaɪɹənmˈɛntəl pɹˈɛʃɚ sɚɹˈaʊndɪŋ ðə lˈɪkwɪd ænd ˈɔːl ðə lˈɪkwɪd tʃˈeɪndʒᵻz stˈeɪt tə ɡˈæs.