ساينس الصف الأول الاعدادي – الفصل الدراسي الاول ساينس اولي اعدادي ترم اول In This part we will study : Heat energy It is a form of energy which is transferred from an object with higher temperature to that with lower temperature. Temperature It is the heat condition which states the direction of heat energy whether from or to the object when it comes in contact with another and it is directly proportional to the kinetic energy of the particles . Heat transfers through different media by three ways 1. Conduction 2. Convection 3. Radiation Transfer of heat by conduction It is the transfer of heat through solids from the part with higher temperature to that with lower temperature. Life application : (G.R) Cooking pans are made up of copper and aluminum. Because they are good conductors of heat. (G.R) When you put a metallic spoon in a cup of hot tea for a time, you feel the hotness of the spoon. Because heat is transferred through solids by conduction. Transfer of heat by Convection It is the transfer of heat in gases and liquids, where hot molecules which have less density rise upwards, while colder molecules which have more density fall down. Life application : 1. The air conditioner is fixed at the upper part of the room. To cool the air in the upper part of the room, where its density increases, so it falls down, while the hot air rises up to be cooled and so on. 2. The freezer of the fridge is found at the top of the fridge. Because when air is cooled, its density increases, so it falls down to cool the food in the refrigerator, while the hot air (with low density) rises up to be cooled again and so on. 3. The electric heater is placed at the bottom of the room. Because when air (around the heater) is heated, its density decreases., so it rises up to warm the room, while the cold air (with high density) falls down to be heated and so on. لمتابعة مستر احمد الباشا وكل ما يخص الساينس : جروب الفيس بوك http://bit.ly/2Of1mcN صفحة الفيس بوك http://bit.ly/2Gq5xMo بالتوفيق مستر احمد الباشا