Globe

My model globe's diameter is about 25cm. Since the globe is a complete sphere, the equatorial diameter and polar diameter are the same.

The average diameter of the Earth is about 12742km or 1,274,200,000cm about 1.3 billion cm!!

(note this is the volumetric average taking into account the "squashed" sphere shape of the Earth)

The diameter of my globe is 25cm.

So the ratio between the two is:

1,274,200,000 : 25

which simplifies to:

50,968,000 : 1

So a distance of 1mm on my model globe would be 50,968,000mm on Earth, that is about 51km!  Which would take about 10 hours to walk at a brisk pace with no stops or rest!  10 hours to walk 1mm; the Earth is big!

Volume

The volume of the Earth is about 1,083,210,000,000,000,000,000 m^3.

That is enough to hold 501 Trillion O² arenas!!

I can calculate the volume of my model globe.

Volume of a sphere is 4/3 x π x radius³

So for my model globe it is:  4/3  x  π  x  0.125³      m³

0.00818 m³

So the volume ratio between the Earth and my model globe is about

1,083,210,000,000,000,000,000 : 0.00818

or about

132,400,000,000,000,000,000,000 :  1

These are big numbers!!!