With A Plastic SpoonEat ice cream with a plastic spoon and you will never experience your tongue stuck to it. Most plastics are not only good electrical insulators—they are good thermal insulators as well. Heat is very slow to pass through a plastic spoon. In fact, plastics usually display conductivity no greater than 0.5 watts per meter per degree Kelvin.
With A Stainless SpoonStainless steel is a metal. As such, it conducts electricity. It also conducts heat. But stainless is by no means the best of heat conductors. Its thermal conduction is about 28 watts per meter per degree Kelvin.
With a Plate SpoonIf you eat ice cream with a silver plated brass spoon, assuming the silver plate contributes little to its thermal behavior, the conductivity is about 115 watts per meter per degree Kelvin.
With A Silver SpoonA solid spoon made of sterling silver is a vastly superior thermal conductor. In fact, its conductivity amounts to approximately 360 watts per meter per degree Kelvin. This is more than 2X the conductivity of the silver plate spoon, more than 12X the conductivity of the stainless spoon, and a whopping more than 600X that of plastic.
What This All MeansThe numbers we’ve been discussing have related to how fast heat is passed through the material in question. How fast does the heat of your moist tongue pass through the spoon and into the ice cream? Let’s look at this from a different angle that will help us understand better.
How fast does the cold from the ice cream pass through the spoon to your moist tongue?
Tongue Stuck To A Silver Spoon?If the ice cream you eat has a temperature equal to or above the freezing point, nothing will happen. But if the ice cream is below the freezing point of water, it can freeze the surface of your wet tongue—if the spoon transfers heat rapidly enough. Sterling silver does exactly that! If you do not want to freeze your tongue to a spoon, choose a spoon made of some other material.
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