If measured in centimeters, the answer will be in cubic centimeters (cm³). Mass is measured in grams. The units for density will be g/cm³. Arrangement of atoms in different metals is similar.

If your students have already learned the meaning of volume and mass, you can easily use those terms to define density as Density = mass/volume and then use those terms in the lesson. NGSS 5-PS1-3: ...

The physical properties of seawater include both 'thermodynamic properties' like density and freezing point, as well as 'transport properties' like the electrical conductivity and viscosity.