Generate interactive temperature vs energy heating curves showing all phase transitions for common substances
Select substance and mass to generate a complete phase change diagram
Configure parameters and click Generate to create an interactive heating curve diagram.
Select from water, CO₂, iodine, or naphthalene with pre-loaded thermodynamic data.
Enter the mass in grams to calculate actual energy values for each segment.
Define starting and ending temperatures to control what phases appear on the diagram.
Get an interactive heating curve with labeled phases, transition points, and energy values.
A heating curve is a graph of temperature vs energy added. It shows how temperature rises, then plateaus during phase changes (where energy breaks bonds instead of raising temperature), then rises again.
During a phase change, all added energy goes into breaking intermolecular bonds rather than increasing kinetic energy. Since temperature measures average kinetic energy, it remains constant until the phase change is complete.
Vaporization requires much more energy than melting because it must completely separate molecules from each other, overcoming all remaining intermolecular forces. For water, vaporization needs 2,260 kJ/kg vs only 334 kJ/kg for melting.
At 1 atm pressure, CO₂ cannot exist as a liquid — it sublimes directly from solid to gas. So its heating curve shows only one plateau (sublimation) rather than two separate plateaus for melting and boiling.
Mass affects the width of each segment (total energy needed) but not the shape. More mass means more energy needed for each phase, stretching the x-axis proportionally. The transition temperatures stay the same regardless of mass.