thermal conductivity class 9 physics

Welcome to my channel ''Lectures of Physics". This channel contains lectures of physics on class 9th, 10th, 11th and 12th in easy way. This video is about thermal conductivity class 9 physics chapter 9 transfer of heat. Thermal Conductivity – 500 Words (Class 9, No Mathematics) Thermal conductivity is an important concept in heat and temperature. It tells us how easily heat can pass through a material. Different materials allow heat to travel at different speeds. Some materials let heat move quickly, while others slow down its movement. This property of a material is called thermal conductivity. If heat passes quickly through a material, we say it has high thermal conductivity, and such a material is called a good conductor of heat. Metals like copper, aluminium, gold and iron are good conductors because they allow heat to move through them very easily. That is why cooking pots and pans are usually made of metals. When you heat one part of a metal spoon, the other end becomes hot after a short time. This happens because the metal conducts heat rapidly. On the other hand, materials that do not allow heat to pass through them easily are said to have low thermal conductivity. These materials are called insulators or poor conductors of heat. Examples include wood, plastic, rubber, glass, paper, wool and air. If you hold a steel cup filled with hot tea, your hand will feel hot immediately. But if you hold a paper or plastic cup, it feels much safer because these materials do not let heat pass quickly. This is due to their low thermal conductivity. Thermal conductivity is closely related to how particles inside a material behave. In solids, particles are tightly packed, so heat travels from one particle to the next very efficiently. Metals are even better because they contain free electrons that move quickly and carry heat energy from one place to another. In insulators, particles are not arranged in a way that allows heat to move easily, so heat flow is slow. Thermal conductivity helps us understand many everyday situations. For example, buildings in hot and cold places are designed using materials with specific thermal conductivity. In hot areas, houses are built with insulating materials so that heat from the sun does not enter quickly, keeping the inside cool. In cold areas, walls and windows are also specially designed so that heat inside the house does not escape easily. Clothes also make use of thermal conductivity. Woollen clothes trap air, which has very low thermal conductivity, so they keep us warm in winter by preventing body heat from escaping. Similarly, thermos flasks keep tea hot for a long time because their walls are made with insulating materials that do not allow heat to pass out quickly. Thermal conductivity is also important in cooking, refrigeration, construction, engines, electronic devices and many other areas. Good conductors are used where we want heat to move quickly, like in cooking utensils or heat sinks of computers. Insulators are used where we want to stop heat from moving, like in winter jackets, oven handles or refrigerator walls. In short, thermal conductivity tells us how well a material can conduct heat. Understanding this property helps us select the right materials for different purposes in daily life. For more amazing lectures please subscribe our channel. For more lectures of class 9th visit link below    • class 9 physics chapter 1 | physical quant...   For more lectures of class 10th visit link    • class 10 physics chapter 10 | simple harmo...   For more lectures of class 11th visit link    • Physics Class 11   For more lectures of class 12th visit link    • Physics Class 12th   #lectures of physics #physics #inter physics #matric level physics #school level physics #fsc physics