The Science of Conduction

Heat travels three In last month’s issue, Lesson

No. 1 reminded us that all energy as we know it comes from the sun. So, for Lesson No. 2, let’s discuss basic energy as it relates to heat in some form or fashion. The sun is a really big blob of heat. I expect you already knew that, but let’s look at how heat affects practically every aspect of our life.

First, I think it is neat, and

not by coincidence, that our earth seems to be the only planet just about the right distance from the sun to support life as we know it. If we were much closer to the source of all energy, it might be too hot. And if we were farther away, it might be too cold. The sun always shines and

affects the earth every second of every day. It is estimated about half of the heat from the sun is absorbed by something on earth. It is not possible for us to list all of  from the sun’s heat, but it is possible to explain how that heat affects our daily lives.

ways – by conduction, convection and radiation. The better we

understand these principles, the better we can understand how a house uses energy. I am going to do my very best to explain these to you with examples that are easy to understand, but remember the only reason I am known as the  because my initials are D.R. According to the Webster

dictionary, conduction is the passing of heat from particle to particle. That means conduction will occur anytime one substance of a certain temperature touches another substance of a different temperature. Your foot touching  tub of water is conduction. Your hand touching a cold windowpane or a hot pan in the oven is conduction. Generally speaking, conduction does not occur in gases such as air. That would be convection and will be covered in the next issue. The speed of the conduction

can be very fast or very slow. If the water in the shower is

105 degrees, you say, “Aaahhh  blast is 140 degrees, like some motels, you may scream instead. Remember a good conductor of heat is not a good insulator and vice versa. Insulation slows the rate of

conduction. A rug or a piece of  bare foot feel a lot warmer. Heat always moves toward cold, and, in this case, the heat simply does not leave your foot as fast as before. Furthermore, not all conduction is a bad thing. Take for instance an electric water heater. The electric element touches the colder water within the storage tank and heats it by conduction. That is a useful form of conduction. Other useful examples are a coffee maker, a frying pan cooking an egg and a  building science could whet your appetite! Next month, I’ll describe how

conductive heat often changes to convective heat. The springtime warmth provides us many examples. Stay tuned for the next lesson.

  501-653-7931.

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