Prep.2 | Science | Methods of Heat Transfer | Unit 1 - Lesson 4 - part 2/2

2. Convection: o The transfer of thermal energy in fluids (liquids and gases) where hotter (less dense) particles rise, and colder (more dense) particles sink. o Life Applications: Space heaters are placed on the floor so warm air rises and cold air descends to replace it. Conversely, freezers are installed at the top of refrigerators so cold air descends and cools the entire space. This method also explains the "sea breeze" phenomenon during the day. 3. Radiation: o The transfer of heat in a vacuum without the need for a material medium (like solar radiation reaching Earth). o Opaque dark objects absorb infrared (thermal) radiation better than shiny, light-colored objects. o Life Applications: Firefighters wear shiny silver clothing to reflect the thermal radiation from flames. Solar heater tubes are painted black to increase their absorption of infrared rays. • Technological and Biological Applications: We also discuss "Thermography," an imaging technique that converts infrared radiation into colored visual images, and how snakes use facial sensory receptors to detect the infrared radiation emitted by their prey at night. بالتوفيق science school