Joule’s law is a linear relationship, that is, the more heat you provide, the greater the temperature change. however, in the previous experiment you plotted time vs. temperature, if you observe closely (e. g. for water) you will see that there is some deviation from a straight line. use your critical thinking to figure out why this inconsistency.

hydrogen bridge

Explanation:

Joule's relationship to heat and temperature is true for all materials where we assume that interatomic forces are linear, when atoms separate these forces decrease. There is a point where the separation between atoms is enough that thermal agitation can separate the molecules and there is a change of state, generally from solid to liquid and from liquid to vapor. When these changes of state are occurring all the energy supplied is used to break the links, so the temperature does not change.

In the specific case of water, there is a bond called a hydrogen bridge that breaks around 4ºC, therefore, at this temperature there is a deviation from the curve since this link is being broken, this does not lead to a change of macroscopic state.

For the other temperatures the water behaves like the other bodies.