ساينس الصف السادس الإبتدئي الفصل الدراسي الاول ساينس سادسة ابتدائي – ترم أول In This part we will study : Oxygen Atmosphere: it is a mixture of gases surrounding the earth. The importance of the atmosphere (G.R) 1. Protect the Earth from the ultraviolet radiation coming from outer space. 2. Adjusts the temperature of the Earth’s surface. Oxygen gas  It forms 21 % of air volume. Nitrogen gas  It forms 78 % of air volume. Other gases Carbon dioxide gas – Inert gases: as ( Helium – Neon – Argon ) – Water Vapor Structure of Oxygen: ► Oxygen exists in a gaseous state. ► Oxygen molecule consists of two oxygen atoms (O2). What is the source of oxygen? Green plants are the main source of oxygen. It is consumed in respiration and combustion processes. ► Green plants are the main source of Oxygen. (G.R) Because it is produced during the photosynthesis process 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