[Nethra K Putti]

EARTH'S COMPOSITION (Composition in % by weights)
99% of earth's mass is constituted by only 8 elements. they are :

1. iron = 35%

2. oxygen = 30%

3. silicon = 15%

4. magnesium = 13%

5. nickle = 2.4%

6. sulphur = 1.9%

7. calcium = 1.1%

8. aluminium = 1.1%

EARTH'S CURST (Composition in % by weight)

1. oxygen = 46%

2. silicon = 28%

3. aluminium = 8%

4. iron = 6%

5. magnesium = 4%

6. calcium = 2.4%

7. potassium = 2.3%

8. sodium = 2.1%

9. others = <1%