Heat Transfer
This led me to the principles of heat transfer. There are three different types of heat transfer: conduction, convection, and radiation. I began with conduction as it seemed the easiest to understand. “Conduction occurs when two objects at different temperatures are in contact with each other. Heat flows from the warmer to the cooler object until they are both at the same temperature”.6 An example of conduction is when you turn on the stove and place a skillet on it. Then, you touch the handle of a skillet. This is where the heat transfers from the skillet to your hand. Another example is when you sit in a chair. Your body heat warms the chair.
Next, I delved into convection. This concept is easier to grasp if you have experience cooking. Research states “Convection occurs when warmer areas of a liquid or gas rise to cooler areas in the liquid or gas. As this happens, cooler liquid or gas takes the place of the warmer areas which have risen higher. This cycle results in a continuous circulation pattern and heat is transferred to cooler areas”.7 Convection occurs when you boil water or use a crock pot. The heat element is at the bottom of the pots and pans. It heats the substance at the bottom and the liquid or gas rises up to heat the middle and top of the substance. This concept should definitely be introduced to young scholars. I had a conversation with a high school chemistry teacher to discuss the vertical alignment of this unit. He stated that high school students struggle all year to understand convection. This type of heat transfer may need more emphasis for scholars to master.
Radiation is the last method of heat transfer that I researched. Radiation is explained thus “it does not rely upon any contact between the heat source and the heated object”.8 If you have ever stepped outside on a sunny day then you have experienced radiation heat transfer. The sun shining down on you and warming your skin is a method of radiation. The heat from a fire warming you is an another source of radiation. An additional example would be a solar oven. The solar oven is warmed by the heat of the sun and then cooks the food inside of it. Everyday examples are toaster ovens and microwaves. The heating elements produce radiant heat. An interesting note, toaster ovens use all three types of heat. They have a radiant heating element, use the convection method and have a metal tray that conducts heat.
Now, the research was much easier for me to understand than the laws of thermodynamics. At least, it did not have me talking to myself in the grocery store as I suddenly made connections. People eyeing my strangely as I mutter “Hmm, so that box of cookies at the top of the pile must be the same temperature as the shelf. That doesn’t seem that complicated. Why did that make my head ache to think about it earlier?” Needless to say, an hour in a grocery store can make more progress in comprehending than trying to force the connection.
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