CBSE ADDA

   CBSE Class 9 - Science - Chapter 10: FLOTATION   Thrust and Pressure, Pressure in Fluids, Buoyancy Fluid: Fluid is a substance that flows.  For example, liquids and gases. They take the shape of container in which they are stored. The study of fluids at rest is known as hydrostatic or fluid static’s.   The study of fluids in motion is termed as hydrodynamics. THRUST:   The normal force acting on a unit surface area of the fluid is called thrust Density: The mass per unit volume of a substance is called density. D = mass /volume  Þ Mass of substance = d x v ------------------------ (i)  SI unit is  kg/m 3 The density of water (1 g cm −3 ) PRESSURE IN A FLUID The pressure (P) is defined at the magnitude of the normal force acting on a unit surface area of the fluid. P = F/A .  Hence pressure is in directly proportional to Area of contact. For example a nail or a knife have pointed and sharp edge to reduce area of contact to ap

Class IX 1st.  Term Science Syllabus April : Unit : Matter in our surroundings Unit : Matter –Is matter around us pure Unit:  Improvement in Food Resources May: Unit : The fundamental unit of life Unit : Tissues July: Unit : Motion Unit : Force and laws of motion August: Unit : Gravitation September : Revision of the I term Syllabus and I term examinations PRACTICALS Class IX 1st.  Term Science Practical are to be conducted alongside the concepts taught in theory classes. List of Experiments 1. To test (a) the presence of starch in the given food sample (b) the presence of the adulterant metanil yellow in dal. 2. To prepare a) a true solution of common salt, sugar and alum b) a suspension of soil, chalk powder and fine sand in water c) a colloidal of starch in water and egg albumin in water

CBSE Science Chapter 10  Reaching the age of adolescence study help by JSUNIL sir Q1. What is adolescence? Ans. It is the period of life when the body undergoes changes, leading to reproductive maturity. Q2. Define puberty. Ans. The stage when human body becomes sexually mature. Q3.  What is adam’s apple? Ans. The growing voice box in boys can be seen as a protruding part of the throat called adam’s apple. Q4. What are secondary sexual characters? Ans.These are the features that help to distinguish males from females. Q5. Define the following terms.  (a) Hormone  (b) Endocrine glands Ans. (a) Hormone- they are chemical messengers for various processes and activities in the body         (b) Endocrine glands- the ductless glands which secrete hormones directly into blood. Q6. Enlist the changes occurring in males and females during puberty. Ans. Type of change In girls In boys Increase in height Su