Science Class 9 English

  CBSE Class 9 Science Revision Notes CHAPTER – 1 Matter in our Surroundings Anything that occupies space and has mass and is felt by senses is called matter. According to indian ancient philosphor, matter is the form of five basic elements (the Panchtatva) – air , earth ,fire , sky and water. Characteristics of particles of matter Made of tiny particles. Vacant spaces exist between particles. Particles are in continuous motion. Particles are held together by forces of attraction. States of Matter Basis of Classification of Types Based upon particle arrangement Based upon energy of particles Based upon distance between particles Five states of matter Solid Liquid Gas Plasma Bose-Einstein condensate (I) SOLID Fixed mass, volume and shape Inter-particle distances are least. Incompressible. High density and do not diffuse Inter particle forces of attraction are strongest. Constituent particles are very closely packed. (II) LIQUID Not fixed shape but fixed volume and mass. Inter partic...

  CBSE class IX Science NCERT Solutions Chapter 1 Matter in our Surroundings (Page No. 3) 1. Which of the following are matter? Chair, air, love, smell, hate, almonds, thought, cold, cold drink, smell of perfume. Ans.  Chair, air, smell, almonds, cold drink and smell of perfume are matter. 2. Give reasons for the following observation: The smell of hot sizzling food reaches you several metres away, but to get the smell from cold food you have to go close. Ans.  Since hot sizzling food has temperature higher than cold food and at higher temperature diffusion rate (movement) of particles is very fast, due to this the smell of hot sizzling food reaches us from several metres away. 3. A diver is able to cut through water in a swimming pool. Which property of matter does this observation show? Ans.  If diver has ability to cut through water in a swimming pool then it shows that the particles of matter have a kind of force working between them. Because of this force the pa...