Keep heating water that is already boiling and the thermometer stays at 100°C: the energy going in is spent tearing molecules apart from one another, not making them move faster. The curve of temperature against heat added therefore climbs and then flattens out exactly twice, and those two plateaus are the latent heat of fusion and of vaporization. For iron the melting point moves all the way up to 1538°C, while dry ice at ordinary pressure sublimes, going straight from solid to gas and skipping the liquid state altogether.
Keep heating water that is already boiling and the thermometer stays at 100°C: the energy going in is spent tearing molecules apart from one another, not making them move faster. The curve of temperature against heat added therefore climbs and then flattens out exactly twice, and those two plateaus are the latent heat of fusion and of vaporization. For iron the melting point moves all the way up to 1538°C, while dry ice at ordinary pressure sublimes, going straight from solid to gas and skipping the liquid state altogether.
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