# Question #623a6

##### 1 Answer

#### Explanation:

We know that marble is a small spherical toy. These come in various size. Most commonly, these are about

It is also clear that number of marbles of smaller diameter required to fill a sphere will be greater than the number of marbles of larger diameter.

Since equatorial radius of earth is greater than the polar radius, therefore we use

Average Radius of earth as

Volume of sphere the size of earth

Radius of smallest marble

Volume of one smallest marble

Number of such marbles which will fill the sphere the size of earth

This calculation assumes: the **marbles are liquid** and we could fit the number calculated above into the larger sphere of the size of earth. Unfortunately, marbles are not liquid. Therefore, there would be inevitable gaps between the marbles. These gaps are related to packing efficiency, which refers to the ratio of the combined volume of the marbles to the total volume of space that these occupy.

In three-dimensional Euclidean space, the densest packing of equal-volume spheres can be achieved by close-packed structures. It can be shown that for equal-volume spheres the densest packing uses approximately

Actual number of