physics paper

Submitted By vmgreen4
Words: 1525
Pages: 7

General Physics I
Project 2 The three means of transmitting heat energy from one place to another is through conduction, convection, and radiation. These three means can be used in so many ways everyday and you not even know it. Conduction is the transfer of heat between two stationary objects caused by a temperature change. Convection is the transfer of heat from one place to another by the movement of fluids. Radiation is the process of which energy is emitted as particles or waves. Each of these we use in everyday lives like using a heating blanket to keep your warm, laying out in the sun to get a tan, and putting your wet shoes on a floor vent to dry them faster. First, we are going to talk about conduction and how using a heating blanket to warm you is considered conduction. Keep in mind that conduction is the transfer of heat or cold between two objects. The basic principle of warming blankets or warming mattress pads is that an electric current passing through a resistive wire generates heat. All electric bedding contains a long length of resistive wire heating element fastened in a serpentine pattern throughout the pad or blanket. Manufacturers created the material by depositing vaporized aluminum onto a very thin plastic film. Modern electric blankets use carbon fiber wires. These wires are far less bulky and conspicuous than older heating wires. Carbon fiber wires are also used as the heating element in many high-end heated car seats. The heat produced is infra-red and can easily warm the body. The resulting material is thin, flexible and thermal-reflective; meaning it reflects heat. The aluminum helps redirect infrared energy, which is just a fancy word for heat. Depending on how the blanket is made, it can reflect heat away. NASA uses heating blankets as well, called space blankets. Sometimes called a passive warming system, space blankets assist the body in conserving that infrared energy. Infra-red heat is safer, is efficient to run and more comfortable to use. Space blankets are a little different that heating blankets for your house on cold nights. Many different people use this like astronauts since it is called a space blanket, surgeons use it for people in surgery because anesthesia makes you have the chills, even runners after marathons their body temperature drops so they use them to keep their temperature up. It is made up of heat reflecting thin plastic sheeting material to keep the body temperature up. They are designed to reduce the heat loss of a body in the form of conduction. It is equivalent to putting aluminum on your body because working as conduction to transfer the heat of one object to the next. So, conduction has to deal with a huge part in your heating blanket or space blanket. Next, we have convection through putting your wet shoes on a floor vent to speed up the drying process or hanging your clothes outside to dry. As we stated earlier, convection is the transfer of heat from one place to another by the movement of fluids. Drying cloth involves two processes. Energy has to be provided to change the water from liquid to vapour and an air stream is needed to remove the vapour. Convection is usually the dominant form of heat transfer in liquids and gases. Although often discussed as a distinct method of heat transfer, convective heat transfer involves the combined processes of conduction (heat diffusion) and advection (heat transfer by bulk fluid flow). The term convection can sometimes refer to transfer of heat with any fluid movement, but advection is the more precise term for the transfer due only to bulk fluid flow. The process of transfer of heat from a solid to a fluid, or the reverse, is not only transfer of heat by bulk motion of the fluid, but diffusion and conduction of heat through the still boundary layer next to the solid. There are two types of convection forced and natural. Convection can be "forced" by movement of a fluid by means other than buoyancy forces. In…