A property of any substance is its density $\rho$(Greek letter rho), defined as the amount of mass contained in a unit volume, which we usually express as mass per unit volume: $$ \rho = {m \over V}$$
The SI unit of density is kilogram per cubic meter ($kg/m^3$).
Fig. 1: Both of the material have similar volumes but lead is more denser than aluminum due to high number of proton and neutron in the nucleus.
For example, aluminum has a density of $2.70 g/cm^3$, and lead has a density of $11.3 g/cm^3$. Therefore, a piece of aluminum of volume $10.0 cm^3$ has a mass of $27.0 g$, whereas an equivalent volume of lead has a mass of $113 g$. The difference of densities between aluminum and lead is due to their difference of atomic masses. The unit for atomic mass is the atomic mass unit (u), where $1 u = 1.660 5402x10^{-27} kg$.
Density is the number of things—which could be people, animals, plants, or objects—in a certain area. To calculate density, you divide the number of objects by the measurement of the area. The population density of a country is the number of people in that country divided by the area in square kilometers or miles.

Do you want to say or ask something?

Only 250 characters are allowed. Remaining: 250
Please login to enter your comments. Login or Signup .
Be the first to comment here!
Terms and Condition
Copyright © 2011 - 2023
Privacy Policy