Understanding Radiation: IGCSE Coordinated Science Lecture Note

p {margin: 0; padding: 0;} .ft00{font-size:27px;font-family:Arial;color:#000000;} .ft01{font-size:16px;font-family:Arial;color:#000000;} .ft02{font-size:16px;font-family:ArialMT;color:#000000;} .ft03{font-size:18px;font-family:Georgia;color:#333333;} .ft04{font-size:16px;line-height:19px;font-family:Arial;color:#000000;} .ft05{font-size:16px;line-height:19px;font-family:ArialMT;color:#000000;} .ft06{font-size:16px;line-height:18px;font-family:ArialMT;color:#000000;} IGCSE Coordinated Science: Radiation Radiation 1. Recognise radiation as the method of heat transfer that does not require a medium to travel through. Radiation (unlike conduction and convection) does not require a medium to travel through. This means they can travel through anything and even empty space (vaccum). The best example would be radiation from Sun. Earth receives heat from the sun through radiation. The heat is transferred through Space (which we know is a huge vacuum) by radiation! 2. Describe experiments to show the properties of good and bad emitters and good and bad absorbers of infra-red radiation. Dark or black surfaces tend to be good emitters and absorbers of heat White or light-coloured surfaces tend to be poor emitters and absorbers of heat. Reflective surfaces will reflect the radiation and heat. An easy experiment can be set up to see if a material is a good or poor emitter/absorber. ● Place different materials of different colour under the sun, or close to a source heat radiation. ● After a period of time, measure their temperature. The dark surfaces should be warmer because they are better absorbers of infra-red radiation. 3. Identify infra-red radiation as the part of the electromagnetic spectrum often involved in heat transfer by radiation. ● Radiation is a type of thermal energy transfer due to Electro-magnetic waves. All hot object emit radiation ● The most prevalent form of heat transfer by radiation is infrared. An example of an electro-magnetic wave is an infrared wave, which is a component of the electromagnetic spectrum. ● It does not matter if you do not know what electro-magnetic waves and spectrum mean! You will learn about them later. Basically they are invisible waves that transfer energy.