The change in temperature is a direct result of the interaction between the heavy metals and the protease enzyme. When the biosensor is dipped in a sample that contains heavy metals, the metals interact with the enzyme, causing it to alter its catalytic activity . This alteration leads to a change in the rate of the enzymatic reaction, which in turn leads to a change in heat production. This change in heat production can be measured as a change in temperature. If there is a gradual increase in the temperature reading on the thermometer, it indicates that the sample is contaminated by heavy metals. On the other hand, if there is no notable change in the temperature, it implies that the sample is heavy metal free.