At point A, the beginning of observations, the substance exists in a solid state. Material in this phase has volume and shape. With each passing minute, is added to the substance. This causes the molecules of the substance to more rapidly which we detect by a rise in the substance. At point B, the temperature of the substance is °C. The solid begins to . At point C, the substance is completely or in a state. Material in this phase has volume and shape. The energy put to the substance between minutes 5 and 9 was used to convert the substance from a to a . This heat energy is called the latent heat of fusion. (An interesting fact.) Between 9 and 13 minutes, the added energy increases the of the substance. During the time from point D to point E, the liquid is . By point E, the substance is completely in the phase. Material in this phase has volume and shape. The energy put to the substance between minutes 13 and 18 converted the substance from a to a state. This heat energy is called the latent heat of vaporization. (An interesting fact.) Beyond point E, the substance is still in the phase, but the molecules are moving as indicated by the increasing temperature.