ساينس الصف الأول الاعدادي – الفصل الدراسي الاول ساينس اولي اعدادي ترم اول In This part we will study : Melting point It is the temperature at which matter begins to change from a solid state to a liquid state. – Matter exists in three states which are solid, liquid and gaseous. – Each substance has a definite melting point which is used to differentiate between different substances. Applications : 1. In making of alloys. a. Copper – gold Alloy: used in making jewels. b. Nickel – chrome Alloy: used in making heating coils. Boiling point It is the temperature at which matter begins to change from a liquid state to a gaseous state . Solid substances are divided according to hardness into Soft solid substances at room ordinary temperature as Rubber. Solid substances become soft by heating to be shaped easily as Metals. Solid substances can’t be soften by heating as Coal and Sulphur. Life applications of hardness : 1. The screwdrivers are made of steel iron. Because it is very hard. 2. The rods used in building concrete houses are made of iron not copper. Because the hardness of iron is more than that of copper. 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