**Annotation category:**

Chapter 2

Note: |

Finding the volume of a sand grain:

The formula for the volume of a sphere is:

V = (4π/3)R^{3},

where R = radius of sphere.

R = 0.25mm = 2.5 x 10^{-1}mm

= (2.5 x 10^{-1}mm)(1m/10^{3}mm)

= 2.5 x 10^{-4}m.

(4π/3)R^{3} ~=
4.18 x (2.5 x 10^{-4}m)^{3}

=
4.18 x (15.6 x 10^{-12}m^{3}

= 6.48 x 10^{-11}m^{3}.

(Review the Scientific Notation tutorial for help here.)