One of the perceived disadvantages is that metal feels cold to the touch. This is why some people prefer things that they’re in regular contact with to be make from another material, like wood or plastic.
Why does metal feel cold? Metal feels cold because it conducts heat extremely well. Since room temperature is lower than your body temperature, metal will quickly absorb the heat from your skin, making it feel cold. This is also why hot metal can burn you so easily; it will quickly transfer its own heat into your skin.
Different kinds of metal will transfer heat at different rates, making some kinds feel colder than others. There are also a few things that you can do to make metal feel warmer and reduce this thermal conductivity. In this post, I’ll go over what metals feel especially cold, and what you can do to make this less noticeable.
Why Metal Feels So Cold Compared to Wood
The short answer is that metal is a thermal conductor and wood is a thermal insulator. Even if the metal is the exact same temperature as the wood, the metal feels significantly colder. This is because the metal will conduct the heat away from your skin, whereas the wood will keep the heat from your skin where it is.
All materials have a rate of thermal conductivity. A common way to measure thermal conductivity is to use Watts per meter Kelvin, or W/m-K, often simplified to “K-value”. This is basically just measuring how many Watts of energy (heat) is transferred over one meter for every degree of difference in temperature.
So if you have a piece of material one meter thick put into a room that’s one degree Kelvin cooler than the material itself, and it loses 1 Watt of energy, it has a K-value of 1.
This might be a little tricky to wrap your head around, so here’s a little table of different materials along with their K-values. This will give you an idea of how quickly they’ll be able to transfer heat. The lower the number, the more they insulate. The higher the number, the more they conduct.
|Wood – Pine||0.11|
|Wood – Oak||0.16|
From that table, you can really see how much of a difference you’ll get between materials in terms of how much heat they can draw away from you.
But how does this make metal feel cold?
Average room temperature is somewhere around 70 degrees Fahrenheit. While our internal body temperature is around 98 degrees Fahrenheit, our average skin temperature on your hands is about 86 degrees.
That means that when you touch something at room temperature, there’s a difference of about 16 degrees Fahrenheit on average.
Now if the object you touch has high thermal conductivity, it’ll absorb the heat from your hand, pulling it away from you. This cooling of your hand makes the object feel cold. The K value will determine how cold it feels because of how quickly it’ll pull the heat away. In other words, a block of stainless steel will not feel as cold as a block of silver (not that you’ll come across this situation very often).
Alternatively, if you’re touching something outside on a cool day, you’ll notice this difference even more. This is what will make your tongue stick to a metal fence – the metal draws the heat away so quickly that your tongue will freeze.
So really, it’s not the metal that’s cold. It’s the same temperature as everything else around you. You’ll just feel the difference more.
But why do materials like wood feel warm?
Because wood is such a good insulator, it prevents heat from being drawn away from your skin. Your skin is cooler than your internal body temperature. This means that your internal temperature will make your skin warmer, which gives you a warm sensation when you touch insulating materials like wood.
Either way, once you’ve been in contact with the material for a while, your skin temperature will balance with the temperature of the material. That’s why metal rings (even silver ones) only feel cold for a second; once you’ve warmed the metal up, it doesn’t feel cold any more.
How to Make Metal Feel Warmer
Since thin metals will warm up quickly, they’ll feel cold for a shorter amount of time. The caveat to that is that you need to be in contact with the metal in the same spot to warm it up. So if you’re holding a metal handrail as you’re walking, you’ll be moving too fast to warm up the metal. It’ll be cold.
However, there is an alternative. If you can keep an insulating barrier between your skin and the metal, it won’t feel as cold.
One common area that we see this is with metal handrails. Fairly often, there will be a soft plastic covering the top of the handrail. This makes that insulating barrier between your skin and the metal, so your hand won’t get cold.
A thick, insulating paint can do something similar. Whether it’s a clear lacquer or colored paint, this will stop some of the heat from being drawn away as quickly.
Powder coating is another popular option. Instead of paint, powder coating melts plastic powder onto a metal’s surface. This coating can be thicker than paint, too. The result is a thermal barrier that will make the object feel warmer.
Kind of Related Questions
Why do pennies turn green?
Pennies turn green because they have a copper coating (pennies have been made from zinc since 1982 and then plated with copper). When copper is exposed to moisture and oxygen, it will start to corrode. This corrosion is called a patina, and it’s greenish-blue.
If you found this to be wonderfully fascinating and want to know more, then check out this article.
Why does metal rust?
Only metals that contain iron will rust. Rust is a chemical reaction that can happen in a few different ways, but the most common is when iron reacts with water and oxygen. This reaction can also take place when the iron reacts with chlorides (found in salt) and oxygen.
Rusting can be prevented by combining the iron with other elements. One of the most common elements for this is chromium, which creates a very thin protective film over the metal, preventing this chemical reaction.
If you want to know how to protect metal from rust, remove rust, and how to make metal rust super fast, you’ll find all of that information here.
Why does steel turn blue when heated?
Ok, this is a cool one.
Steel turns blue because of a thin oxide layer that forms on the surface of the metal. This layer is so thin that it interferes with light waves. It’s a phenomenon known as the thin film effect. It’s also the same phenomenon that makes oil on water or soap bubbles look like a rainbow.
Basically, the thickness of the film will determine which wavelengths of light will be reduced and which ones will be enhanced.
If you want a full explanation of this really cool effect, then you can get a complete description in this article.