A Method to Calculate the Mass of our Earth and Total Number of Water Drops in it

Though it looks like a very difficult job, it'll be really interesting if you go through these following calculations. These calculations are very simple and the method that has been used here may recollect our school days where we may have studied about radius, volume and total surface area of sphere. We know that our Earth is a great elliptical sphere and we need only the average density, radius of earth and average depth of seawater to calculate both the mass of earth and total number of water drops in it.

Method for Calculate Mass of Earth in Gm

To calculate the mass of this great Earth we need only the following two things

1. Radius of Earth
2. Average Density of Earth

It has been already known by scientists that the radius of earth is about 6,378 Km. Normally the soil density is calculated as 2.6 gm/cc. But, the presence of larva (molten iron) in inner and outer core of the earth is naturally giving a rise to its overall density and its average density comes as 5.5 gm/cc. Now we can easily calculate the mass of our Earth as we have known both radius and average density of our earth.

In science, density is defined as mass per unit volume (i.e.) d (density) = m/v

Formula to find out the volume of earth or any sphere is 4/3*3.14*r^3

Before substituting the value for' r', we need to convert the radius of earth into cm which comes as 6.378*10^8 cm

Now we can calculate the total volume of earth as follows

4/3*3.14*6.378*10^8*6.378*10^8*6.378*10^8

=1.0862*10^27 cc

Now we can get the mass of earth by multiplying its volume and average density as follows

d=m/v
m=v*d

So, mass of the earth is = 1.0862*10^27 cc * 5.5 gm

= 5.974*10^27 gm

Method to Calculate Total Number of Water Drops in our Earth

It is true that that about 71% of earth surface has been covered by seawater and it is estimated that average depth of sea is 4000 m (13,000 ft)

To calculate the total number of water drops in our great globe we simply need only the following things

1. Radius of Earth (6.378*10^8 cm)
2. Average depth of sea (4*10^5 cm)

First we need to calculate the total surface area of our earth. Formula to find out the total surface area of earth or any sphere is 4*3.14*r^2

Now we can substitute the value of ' r' to get the total surface area of the earth. But, only 71% of earth surface is covered by water. So, the total area of seawater on the earth is = 4*3.14*6.378*10^8*6.378*10^8*0.71 sq.cm

Average depth of sea is 4*10^5 cm

Now the total volume of seawater in our earth is = 4*3.14*6.378*10^8*6.378*10^8*4*10^5*0.71 cc

= 1.451*10^24 cc

Every 1 cc of water contains 20 drops of water. All the river and lake water in our earth constitute only 1% of total water in our earth. So, the total number of water drops in our earth including all the oceans, lakes and rivers is = 1.01*1.45*10^24*20

= 2.92*10^25