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 This is how thermal radiation keeps you warm
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Description:

Thermal radiation can be found everywhere from antique radiators and campfires to modern patio heater systems. 

 

Transcription:

Every time you turn on your trusty air fryer or reheat last night¡¯s left overs in the microwave you¡¯re using THERMAL RADIATION. Thermal radiation does more than just keep us fed, though. It also keeps us warm. From antique radiators and campfires. These sources of heat all utilize thermal radiation and help us get through the coldest months of the year. First, we have to understand the concept of heat transfer or how heat is able to travel from its source to its destination. There are three ways it can occur. THERMAL CONDUCTION. THERMAL CONVECTION. THERMAL RADIATION. All of which probably occur right in your home THERMAL CONDUCTION two objects must make direct contact for heat transfer to occur. The simplest example of this is boiling water in a kettle. The heat source the flame coming from a stovetop gradually heats up the kettle because the kettle is in direct contact with the water inside. Heat is transferred from the surface of the kettle to the water. Eventually it comes to a boil. So how does heat spread throughout the water? THERMAL CONVECTION. This method of heat transfer requires fluids such as water or air to conduct heat. In our kettle hot water molecules move faster and rise above the more dense cold water molecules. The constant sinking and rising of the water molecules creates a current. Once all the water molecules inside reach a high enough median temperature. They form water vapor which floats to the surface as bubbles and then into the air. Thermal Radiation requires neither of these conditions to conduct heat transfer. As its name suggests it is a form of radiation. Instead of requiring a medium to transmit heat h travels directly from its source into its surroundings via electromagnetic waves. Depending on its wavelength this can range from the shorter ultraviolet waves all the way up to the longest infrared waves the energy from infrared radiation causes molecules to move releasing energy that is felt as heat. This process happens very quickly literally at the speed of light. Because it does not require atoms or molecules. It can move through the vacuum of space. This makes thermal radiation by far the most efficient and fastest method of heat transfer. And yet there's an even better more obvious example of thermal radiation that everyone is guaranteed to be familiar with. THE SUN. How else would its heat travel millions of miles across the vacuum of space and to the pale blue dot we call home? Essentially the Sun is a gigantic incredibly hot surface with temperatures high enough to generate enough thermal energy to reach far into the Solar System. At its core it reaches 27 million degrees Fahrenheit while the surface temperature measures in at about 10 000 degrees Fahrenheit. THAT¡¯S A LOT OF HEAD. However, it's not just particularly hot objects that emit thermal radiation. Everything radiates thermal energy to some degree. Even cold objects like ice cubes. When ice melts the solid ice particles absorb heat energy from the warmer air giving the particles energy and causing them to move apart. It is comforting to know that regardless of whether or not we fully understand it we're free to appreciate and enjoy its effect. After all, it doesn't take a Ph.D. to enjoy a cozy evening by a roaring fire. 

 

Questions: 

1. In detail, how exactly does Thermal Radiation work? 

2. What is Thermal Convection?

3. What is the better example of thermal radiation? How?

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2022-02-21 ¿ÀÀü 11:05:29
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