# Teaching Kids the Fundamentals of Mass and Weight Measurement

When children are inquisitive about the world around them, it’s important to fuel their curiosity by teaching them the fundamental concepts of measurement. This will help them effortlessly grasp more complex concepts like chemistry and physics later on.

Mass is one of the seven SI base measurement units. It is measured using a balance (not a scale). A balance takes the force of gravity into account when measuring an object’s weight.

## Units of Mass

It is important to teach students that mass and weight are not the same. Students should also know that an object’s mass depends on the amount of matter in the object, but its weight changes depending on the force of gravity in different locations.

In order to teach this concept, students can try a simple experiment. Ask students to hold a pen and a bottle of water in their hands, then determine which feels heavier. They can also compare the results on a scale.

When measuring mass, the most common units are kilograms (kg) in the International System of Units and grams (g). A metric ton is another unit that can be used when measuring large objects. In the United States, we commonly use pounds and pounds per square inch. However, the metric system of centimeters (cm), grams and seconds is used worldwide. This system is known as the CGS system. A competing system is the MKS system, which uses meters, seconds and kilograms as its base units.

## Density

Density is a measure of how much mass an object has per unit of volume. It is a pure property of matter, meaning that it does not change when the quantity of matter changes. Density varies depending on the type of matter, with solids having higher density than liquids and gases.

A precise measurement of an object’s density is required for accurate applications across many fields, from manufacturing to atmospheric studies. Understanding the density of materials is key to creating lighter, stronger, and more durable products. It also helps meteorologists create more accurate weather forecasts and airplane pilots determine optimal flight paths.

Measuring an object’s density requires a balance or other high-precision instrument and a container to hold the sample. The ability to control temperature and pressure during the process is essential for consistent results. Contamination can also skew measurements, so it is important that samples be free of foreign matter. Using standard units of measurement and eliminating environmental factors can help achieve consistent density measurements.

## Inertia

Inertia describes the resistance of a body to changes in motion. An object with greater inertia will require a larger force to change its motion than an object of lesser mass.

It’s important to have the right tools for measuring mass, especially when stability is a factor as in aerospace design. Measuring an object’s mass moment of inertia (MOI) about various axes is critical for designing and manufacturing aircraft and spacecraft.

Using an inertial balance, engineers can determine the object’s mass MOI. The inertial balance uses a spring mechanism that oscillates at a specific frequency and measures the time it takes to complete one full cycle. This is an accurate way to measure an object’s inertial mass. It is also safe to use in microgravity environments such as those found in the International Space Station.

## Gravity

The gravitational force that holds the planets together and pulls on your body and everything else in the universe is measured by comparing an unknown mass to another known one using a balance scale. This method of measurement works because the accelerations of the two masses will be the same (although it does break down near supermassive objects such as black holes).

It’s important to note that although mass and weight are sometimes used interchangeably, they are different things. Mass is the total amount of matter, or “stuff,” in an object; weight is the force of gravity on that matter.

The value of the universal constant G (which represents the strength of gravity at a given location) varies slightly depending on latitude, elevation and subsurface density; however, these variations are usually less than 1% of the overall value. This allows for a great deal of accuracy in measuring an object’s gravity and solving for its mass.