Question

a glass bead weighs 0.281g and has a radius of 2.5mm and displaced 0.3ml of water. Calculate the density using the diameter of the bead and then calcualte using the volume by displacement. Then state which one you think is more accurate and why.

Answer 1

A glass bead is an spherical glass so volume of a sphere is:

V = 4/3 pi r³

So let's calculate the volume first:

V = 4/3 * 3.14 * (0.25)³

V = 0.065 cm³ or 0.065 mL

d = m/V

d = 0.281 / 0.065 = 4.3231 g/mL

Using now the displacement of water:

d = 0.281 / 0.3 = 0.9367 g/mL

It's more accurate the one with the calculus of the volume of the sphere, because it0s a figure with a determined form, and it's including the whole space of the glass. Volume is the space that occupies a matter, so, this would be more accurate.

Hope this helps