It is the result obtained by graphing the increase in water temperature with respect to the time in which it is faced with heat. To have a heating curve, it is necessary to use a solid container (made of insulating material), fill it with water and subject both to heat.
The solid begins to absorb heat which will be transmitted to the water, which will be presenting an increase in its temperature, up to boiling and thereafter the temperature rise and stop enter a process of boiling.
When comparing the variation that the temperature presents, with respect to time, what is known as the heating curve is generated.
Said heating curve can be used not only with water, which is a liquid, which (reached its maximum temperature) can turn into gas. But also with a solid that can be transformed into a liquid and finally end up in a gas.
It is called a curve because that is the shape the graph takes. To obtain it, a vertical line (y-axis) that will represent the temperature is drawn, which is intertwined with a horizontal line that will represent time (x-axis). By joining the points of coincidence between temperature and time, the heating curve will be obtained.
The graph will obtain its curvature when starting with a very vertical inclined line that will become more and more horizontal. When the graph remains horizontal, it is because the temperature has been maintained over time, this occurs when the element subjected to heat is at its maximum temperature, that is, where it will experience the change of state (from solid to liquid or from liquid to gas).
If the graphing process starts with an element in solid state, the heating curve of this will remain horizontal when it changes to a liquid state and once that transformation is finished, the curve starts (again) with the very vertical inclination, until that liquid reaches its maximum temperature, the curve becomes a horizontal line again and boiling (change from liquid to gas) is reached.
It is called " latent heat of fusion ", at the maximum temperature of a solid in its change from state to liquid and "latent heat of boiling", at the maximum temperature of a liquid in its change from state to gas.
