Weight is one of the most common measurements used in our society. Weight is commonly used as a measurement of mass. But, it is also used to measure the gravitational force on an object. Because of the two uses, it can often become confusing on how it is measured and mistakes can be commonplace when you misinterpret measurements.
When it comes to mass, weight is a measurement of comparison. Mass is one of the measurements used to calculate density. When you visit the doctor, they may have you stand on a set of scales that uses small weights to balance an arm that measures your weight. This scale is not affected by changes in gravity and measures your weight, or mass, in comparison with the known mass of a small weight. This type of scale is not affected by changes in gravitational pull.
Many times, an electonic scale may be used. This scale measures the amount of pressure that your weight applies to a surface. Because it is measuring the amount of gravitational force the Earth is applying to your body, it will change with how far you are from the center of the Earth, or it could even change if the moon is directly above and the moon’s gravity is counteracting the gravity of the Earth.
I know this can be confusing. Just remember to think about what you are actually measuring. Are you comparing weight to a known mass like on a counterbalance scale, or are you measuring how much force the Earth’s gravity is pulling down on an object.
To add to the confusion is the separate standards for measuring weight. There is the U.S. Standard and their is the Metric System. The metric system uses a base unit of weight/mass called the gram and then larger and smaller units are derived from the gram in powers of 10. For example, a milligram is 1/1000th of a gram and a kilogram is 1000 grams.
The U.S. Standard is a little more difficult to calculate. There are different weight units. For example, you have the ounce, pound, and ton. One ounce is 1/16th of a pound and one ton is 2,000 pounds.
Not only is it important to be able to convert within one system of measurement, like calculating how many ounces are in a ton, but also to be able to convert from U.S. Standard measurements to Metric.
For some practice on converting weight and mass measurements, try using these calculators: