Question

Approximately determine the number of cells in the human body. Model the human body with a cylinder 1.9 m high and with a radius of 0.1 m at its base. Model the cell with a cube with an edge length of 10µm.

Answer 1

Let's first find the volume of the cylinder:

$$V_{c}=\pi r^2h=\pi\cdot(0.1\ m)^2\cdot1.9\ m=0.06\ m^3.$$

Let's find the volume of the cell:

$$V_{cell}=a^3=(10\cdot10^{-6}\ m)^3=1.0\cdot10^{-15}\ m^3.$$

Finally, we can determine the number of cells in the human body:

$$N=\dfrac{V_c}{V_{cell}}=\dfrac{0.06\ m^3}{1.0\cdot10^{-15}\ m^3}=6.0\cdot10^{13}\ cells.$$