Introduction The moon completes one rotation around its axis in 29 days and the same time it takes to complete one revolution around the earth.

Introduction Surface tension explains why Bubbles are spherical. Water doesn’t spread on some surfaces but forms droplets. Oil and water don’t mix; water wets us

  Introduction Threshing: Beating stalks to free grains Winnowing: Separate lighter and heavier components of a mixture by blowing air. Sieving: Separate components of different

Introduction What is Sound? Sound is produced by vibrating objects. Vibrations cause compressions [high pressure] and rarefactions [low pressure]. Sound waves travel through a medium

Introduction This is either contact [friction, muscular] or non-contact [magnetic, electrostatic, gravitational, pressure] Pressure Pressure is inversely related to the area. So smaller the area,

Introduction When a solid is heated the kinetic energy of the molecules is increased and it overcomes the force of attraction of molecules and the

Introduction Acid [pH <7] – Sour, Base [14 > pH > 7] – bitter and soapy to touch. Water soluble base –alkali. Turmeric, litmus [obtained

Conductors and Insulators Conductors –allow electricity to pass through them. Due to free electrons present on their surface. [Metals, Human body] Insulators – Don’t allow electricity to

Introduction Light is made of seven colors. Violet [lowest wavelength] bends most when passing through a prism and red [highest wavelength] least. This phenomenon is

Climate Air moves from a region of high air pressure to low air pressure. Air when heated rises as it becomes lighter. Air expands on

Laws of Motion Newton’s laws of motion First law [law of inertia]: An object remains in the state of rest or uniform motion till a

  Human Hormones     The pituitary gland is an endocrine [ductless] gland. The hormones of the pituitary gland stimulate testes and ovaries to produce their

Introduction The male has two chromosomes X and Y, the female has only X chromosomes. During reproduction, if the X and X chromosomes come together then

  Introduction It can be asexual or sexual. In asexual, new plants are obtained without seeds and in sexual they are obtained from seeds. Vegetative

Introduction Ecology – the study of the relationship between organisms and the environment Ecosystems – functional unit of nature encompassing interaction between its biotic and abiotic components.

  Introduction Ball and Socket joint – The rounded end of one bone fits into the cavity of the other bone. Such a joint allows movement

  Introduction Soil has the following layers: Topsoil or A-Horizon: Humus, the topmost layer, retains water, and provides shelter to organisms B-Horizon: Middle layer, harder and

  Introduction Herbs – Plants with green and tender stems and almost no branches. E.g: Tomato – Herb Shrubs – Branches near the base, thin but hard

  Introduction 22 March is World water day. UN recommends 50 liters of water per person per day. 2003 was the international year of freshwater

Introduction Homogenous mixtures have a uniform composition throughout e.g. salt water and sugar water, tincture alcohol [iodine+alcohol]. Solid solutions like alloys [brass = zinc + copper]

  Introduction Metals are malleable [can be beaten into sheets], ductile [pulled into wires] and conductors of heat and electricity, and sonorous [produce ringing sounds when

  Introduction    Fabrics like cotton, silk are made of yarns and yarns are made of fibers. Types of Fibers: Natural Fibers: Cotton, jute [plant], silk [cocoon of

  Introduction    Bodies of organisms are made of tiny units called Cells. Cells have an outer boundary called a cell membrane [made up of lipids

  Introduction Microorganisms are of four types: bacteria [TB, typhoid, cholera, diphtheria, and plague], algae, protozoa [dysentery, malaria], and fungi. Virus [jaundice] reproduces only inside

  Introduction     Blood contains a fluid part called plasma. Red blood cells [erythrocytes] have red pigment hemoglobin which binds oxygen and transports it to all cells.

Introduction Components of food necessary for the body are called Nutrients. Organisms that prepare food themselves from simple substances are called Autotrophs and animals that take in ready-made

🔹Father of the Indian space program Ans: Vikram Sarabhai 🔹First rocket launching station in India Ans : Thumba(1962) 🔹First rocket launched from Thumba Ans :