Class 10th Class 6th Class 7th Geography

Structure and Interior of the Earth NCERT Notes on Geography

Interior of the Earth


Earths Structure
  • The internal structure of the earth is layered.
  • The Earth is generally divided into four major layers: the crust, mantle, inner core, and outer core.
  • Earth’s crust is the outermost layer composed of various types of rocks.
  • Below the crust lies the Lithosphere
  • These lithospheric plates appear to “float” and move around on the more ductile asthenosphere
  • The boundary between the crust and mantle is generally called the Mohorovičić discontinuity
  • The continental crust is thicker in comparison to oceanic crust.
  • The lithosphere is the upper 80 Kilometers layer composed of both the crust and part of the upper mantle
  • Earth’s mantle is a rocky shell about 2,890 Kms thick that constitutes about 84 percent of Earth’s volume.
  • The outer core is in the liquid state.
  • The inner core is in solid-state.

Earth’s Crust-

  • There are two types of earth’s crust
Oceanic Crust Continental Crust
  • The oceanic crust is thinner
  • It is composed of basalt
  • It has a high density
  • The continental crust is thicker
  • It is composed of Granite
  • It has low density
  • The low density helps it to flow over the oceanic crust


Earth’s Mantle

  • Earth’s mantle has olivine rock.
  • The temperatures increase with depths.
  • The temperature is lowest near the crust and increases with depth.
  • The highest temperatures are found near the mantle material as it is in contact with the heat-producing core.
  • This steady increase of temperature with depth is known as the geothermal gradient.
  • This temperature difference responsible for different rock behaviors, and the different rock behaviors are used to divide the mantle into two different zones.
  • Rocks in the upper mantle are cool and brittle, while rocks in the lower mantle are hot and soft (but not molten).
  • Rocks in the upper mantle are brittle enough to break under stress and produce earthquakes.
  • However, rocks in the lower mantle are soft and flow when subjected to forces instead of breaking.
  • The lower limit of brittle behavior is the boundary between the upper and lower mantle.

Earth’s Core

  • It is composed of alloys of iron and nickel
  • the core gives heat to the inside of earth
  • the radioactive material which is present inside it release heat as they break down into more stable substances.
  • The core is divided into two different zones.
  • The outer core is a liquid because the high temperatures melt the iron-nickel alloy.
  • The inner core is a solid even though its temperature is higher than the outer core because of very high pressure from the weight of rocks lying above it .

Mineral and Energy Resources : NCERT Geography Lesson For class 10th

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Class 6th Science

Diseases Due To Imbalance in Diet NCERT Science for Class 6th Chapter 2

Disease Due to Imbalance in Diet

Imbalance in diet occurs due to following reasons

  • Inadequate quantity of food
  • Excess quantity of food
  • Eating food lacking some essentials component


  • The disease or conditions arising because of inadequate or unbalanced food is called malnutrition.
  • The disease occurring because of inadequate quantity of food is called deficiency disease
  • Over nutrition causes obesity or over weight.

Obesity in Childhood

Effect of Obesity 

  • When we eat more , than we work the body accumulates fat and our weight increases
  • Obesity causes heart diseases,high blood pressure and diabetes.

Disease caused due to deficiency of carbohydrates

  • Carbohydrates gives us energy.
  • Lack of carbohydrates leads
  1. Body weakness
  2. Loss of stamina, as we need sufficient quantity of energy for performing various functions

Disease due to deficiency of proteins-

  1. Lack of proteins leads to kwashiorkor and Marasmus

Symptoms of Kwashiorkor

  • Protruding belly
  • Dark and scaly skin,brownish hair
  • Stunted growth
  • Loss of appetite
  • Anemia
  • Mental retardation

Symptoms of Marasmus

  • Poor muscle development
  • Bones showing through the skin
  • Weak legs
  • Loss of appetite

We should eat enough milk,eggs,pulses,

Disease causing because of deficiency of vitamins

  • Vitamins are required in small quantities for our body
  • Vitamins help us in keeping our eyes ,bones , teeth and gums healthy.


Read Here Food Where Does it Come from Class 6th Notes 

Class 6th Science

Food:Where Does It Come From For Class 6th NCERT Science

Food:Where  does it come from

Food-These are substances from which an organism derives energy and materials for its growth and maintenance

  • The food which we eat at a particular time of a day is called Meal.
  • Usually we consume Three main meals – Breakfast,Lunch,Dinner

Ingredients-The things needed to prepare any food is called ingredients

  • For Example to prepare Chicken Curry We need Raw Chicken,Oil,Masala,Salt,Water.

On the basis of Foot Habits organisms can be classified

  1. Herbivores – Animals eating plant products are called Herbivores
    Example- Cow,Goat,Elehant,Deer

  1. Carnivores-Animals eating animals are called Carnivores
    Example- Lion,Tigers etc.
  1. Omnivores-Animals eating both plants and animals are called omnivores
    Example-Bear,Human,Crow,Cockroaches etc.

Why do we need food ?

We need food for

  1. To get energy required to perform various functions of body
  2. For Growth
  3. For repair of damaged or injured body parts
  4. For protection from diseases and infections

Sources of Food


  • From Plants we obtain Cereals,Pulses,Vegetables,Fruits,Spices,Sugar,tea and Cofee
  • Cereals- They are rich in carbohydrates
  • These are grains of a plant

Pulses or Legumes(Dals)

  • They are rich in Protein
  • Examples-pea,bean,groundnut,Soyaben and Gram



  • They are rich source of vitamis,Minerals and roughage .
  • Water content in vegetables are very high
  • Root Vegetable- Carrot,Sweet Potato,Radish
  • Leafy Vegetable-Spinach,Lettuce,Cabbage ,Methi(Fenugreek)
  • Stem Vegetable- Potato,Onion
  • Fruit Vegetable-Tomato,Bringal,Lady-finger,

Fruits-They are ripened ovaries of flower

  • They are rich in Vitamins and Minerals.
  • Example- Banana,Apple, Mango etc.


  • Major oil yielding plants are cotton,mustard,coconut, and sunflower.
  • Spices-They are used for adding flavours to food.
  • Examples-ginger,cumin,turmeric,pepper etc.

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Animals as a source of food

  • Milk yielding animals- cow ,buffalo
  • Meat- yielding animals-Sheep,Goat,Pig.
  • Poultry animal- animal which provide as both meat and egg are called poultry animals.
  • Example-Hen,Duck etc


  • The egg has yellow portion called yolk and is rich in fats and lipids
  • The white portion is called albumin and is rich in protein .
  • The egg shell is made up of calcium carbonate
  • Fish- fish is rich in animal protein .
  • It is also rich in vitamin D
  • Rearing and management of fish on a larger scale is called pisciculture.
  • Freshwater fish – Catla.Clarius,Barbus etc.
  • Seawater fish- They are rich in protein and iodine.
  • Hilsa,catfish,Bombay duck

Honey Bees

  • Honey bees- Rearing of honey bees is called Apiculture.
  • The insects which provide as honey are called honey bees.
  • The nest of honey bees where nectar are stored is called beehive.
  • The small compartments of beehive is called combs.
  • The place used for rearing of honey is called apiary.

Some steps to avoid wastage of food- should not be allowed to get spoiled or eaten away by animals like rat and squirrel.

2.we should eat only that much quantity of food whic is required by our body.

3.In parties or even in our homes we should not leave food uneaten in our plates.