How to Calculate Scrap Silver Weight

The weight of any object composed of a single material, like scrap silver, directly relates to the object's volume and weight density. Weight density measures how tightly the matter that comprises an object is compacted. For example, the density of silver is 0.41 pounds per cubic inch. Volume describes how much physical space an object occupies. You can calculate the total volume of scrap silver using Archimedes' principle, even if you have multiple, irregularly shaped scraps.

Things You'll Need

• Tape measure
• Calculator
• Graduated cylinder

Instructions

Rectangular Scraps

1. Measure the length, width and height of the piece of scrap silver in inches. For example, say you measure a length of 3.0 inches, a width of 2.0 inches and a height of 1.5 inches.

2. Multiply the length times the width times the height to obtain the volume in cubic inches. In our example, 3.0 inches times 2.0 inches times 1.5 inches equals a volume of 9.0 cubic inches.

3. Multiply the volume by the weight density of silver to obtain the scrap metal weight in pounds. In our example, 6.0 cubic inches times 0.41 pounds per cubic inch equals a weight of 3.69 pounds.

Irregular Scraps

1. 

   Placing the scrap metal in the beaker makes the water level rise.

   Fill a graduated cylinder with 400 ml of water.

2. Drop the scrap silver into the beaker so that it is completely submerged. Record the new level of the water. For example, the new water level might be 435 ml.

3. Subtract the final water level from the initial water level to obtain the volume in milliliters of the scrap silver. This follows from Archimedes' principle, which states that the amount the water level rises equals the volume of the submerged object. Performing this step yields a volume of 35 ml for the piece of scrap metal.

4. Divide the volume by 16.39 to convert it to cubic inches, since a cubic inch contains 16.39 ml. In this case, dividing 35 ml by 16.39 equals 2.14 cubic inches.

5. Multiply the volume by the weight density of silver to obtain the weight of the chunk of scrap metal. In our example, multiplying 2.14 cubic inches by 0.41 pounds per cubic inch equals 0.88 pounds.

References

• Georgia State University: HyperPhysics: Density
• "Physics for Scientists and Engineers with Modern Physics"; Raymond A. Serway and John W. Jewett; 2009
• Wolfram MathWorld: Volume
• Georgia State University: HyperPhysics: Archimedes' Principle
• Engineering Toolbox: Volume