The science of cold

What does it mean when something is cold? Why does wind chill matter? How do things cool off? And finally, can your tongue really freeze to a metal pole in winter?

What is temperature?

First, there really is no such thing as cold. Temperature is a measure of how much energy the particles of a particular object has. An object with a higher temperature has particles with more energy than an object with a lower temperature. There is no such thing as cold because cold is really just an absence of heat or energy.

We all know that temperature is measured with a thermometer. A thermometer measures the force of the particles that are hitting it to determine how much energy is in those particles. If the particles are hitting with a lot of force, the liquid in the thermometer will rise further than particles hitting with just a little force (cold).

You can prove that warm things have more energy and particle movement by blowing up a balloon inside and measuring the circumference of the balloon. Now, take the balloon outside on a cold day. Wait a few minutes and measure it again. The balloon will be smaller. Did the balloon leak? Probably not. The air molecules inside the balloon slowed down and hit the sides of the balloon with less force. Go back inside and measure the balloon again. It will be bigger again as the molecules are now moving faster.

Cooling off and heating up

We spend so many minutes of our day heating things up or cooling things off. This process is really simple if you think about temperature as energy. The big rule to remember is that thermal energy will always travel from hot to cold. Always! This makes a lot of sense because remember, cold is just the absence of heat. A cold object can’t transfer energy it doesn’t have to warm something up. In other words, you can’t share what you don’t have.

So, if you are holding a cup of hot chocolate, the heat energy from the hot chocolate is going into your hands. Energy is being added to your hand so it feels warm. But if you are holding a glass of ice water, your heat energy is going into the ice water. You are losing heat so this makes your hand feel cold.

If you are ridiculous enough to stick your tongue on a frozen pole in winter, the heat energy from your tongue will rapidly go into the pole. The thing is, the pole is very large and is made from a very good conductor of energy. Your tongue’s energy will race into the pole and in just a few seconds the outside layer of your tongue will lose so much heat it will freeze to the pole. This will hurt very much, so don’t do it.

Is wind chill real?

We have had some very low wind chills this year. Often, meteorologists will report the wind chills in winter more than the actual air temperature. The truth is that wind does not make anything colder — ever. If you put a thermometer outside with a fan on it and another thermometer outside with no wind they will both register the exact same temperature because the air still has the same amount of energy in it.

Wind chills create the perception that your skin is colder — but it is not. However, your body releases heat and that heat creates a very thin, invisible layer around your body. Strong winds will blow that heat away but your skin temperature will never actually drop below the real temperature no matter what the wind chill is.

Very low wind chills will make your bare skin feel colder than it really is. This is going to be a big problem for you if you are standing outside at the bus stop naked (don’t do that). If you are wearing adequate clothing your will be fine in the cold and wind. It won’t be at all pleasant but you will be fine — if protected.

This may bring up the question of why schools are sometimes closed for very low wind chills. The simple answer is that most places are not used to the very low temperatures and are not prepared for them. Schools close to protect those who may not have the proper clothing to protect themselves. This is understandable since we don’t often experience temperatures so low.

Mike Szydlowski is the science coordinator for Columbia Public Schools.