Question

Our sense of touch is not always a reliable guide to the degree of hotness of an object.What does it means ?​

Answer 1

Say you dip your hand in hot water. Then you dip in cold water, you are not essentially sure to feel the temperatures as you would have perceived without having dipped your hand in hot water at the first place.

This factor also magnifies on a larger scale.

Thus we need to use thermometer.

Answer 2

A normal human being can baer 98.6F or 37.0C degree of hotness only .Thus our sense will not guide us to know the hotness of an object more than above two degree .For that We need a instrument i.e. thermameter.