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How to Get the Density of a Wooden Sphere

Scientists use density to describe the ratio of an object's mass to its volume. Working in the metric system, a common unit of measure is grams of mass per cubic centimeter (g/cc) of volume. You can find the density of a sphere by first finding its diameter, then calculating its volume. This, together with its mass, will allow you to calculate density.

Things You'll Need

Ruler or calipers
Scale
Calculator

Instructions

- 1
  Measure the diameter (the side to side width) of the sphere. You can use calipers if they are available, or a ruler. You may have to estimate the diameter somewhat if you use a ruler, since the ruler will not lie flat against the sphere. For example, say that you measure a wooden sphere and find a diameter of 10 cm.
- 2
  Divide the diameter of the sphere in half to obtain the radius, r. The radius is the distance from the center of the sphere to the outer wall, moving in any direction. In the case of the example, you would divide 10 cm in half to obtain a radius of 5 cm.
- 3
  Calculate the volume of the sphere using the formula V = 4/3(pi)r^3, where pi is the mathematical constant with the approximate value of 3.14. Your result will have units the same as your radius, but cubed. In the case of the example, you would calculate the volume as 4/3(3.14)5^3, or 523 cc.
- 4
  Weigh the sphere and record its mass. Say the sphere in the example has a weight of 500 g.
- 5
  Divide the mass of the sphere by the volume which you previously calculated. You have now derived the density of the sphere. For the example, you would divide 500 g by 523 cc to get a density value of 0.96 g/cc.

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