Re: Why is marble colder than the surrounding air? And how colder is marble?

It is a common misconception that marble (or any stone or metal) is colder than 
its surroundings. It is not. If it were, you could extract power from the 
temperature difference which would violate the laws of thermodynamics that make 
perpetual motion impossible.

The misconception occurs because the heat capacity and thermal 
conductivity of stones and metal is higher than most other objects in our 
environment. Even though they are at ambient (science-speak for "room") 
temperature, they "pull" heat from our hands faster because energy flows 
faster out of our hands to raise the temperature of the stone than it does with 
wood or plastics. So it cools our hand faster, even though it is not colder.

Hope this helps, even though most people seem to have trouble accepting it 
because their senses them it isn't true. Try measuring the temperature with a 
thermometer before you come back to argue. Sometimes your senses lie to you.

David Winsemius, MD, MPH
Admin, MSN