People measure mass all the time, for example using a balance. This works great if the object stays the same shape and location – but what happens if you go to a different planet?
This is where the concept of weight comes in. It decides the strength of gravitational attraction for different bodies and also determines resistance to speeding up through a force – its inertia.
What is mass?
Mass is the amount of matter in an object. A large object has more mass than a smaller one. The more matter an object has, the heavier it is. An easy way to broach this topic with children is by giving them a pen and a bottle of water. Ask them to compare which feels heavier. This will give them an insight into the concept of weight and why a larger object has more mass than a smaller one.
The term “weight” often gets confused with the term mass. This is because both are used in everyday life, but they have different physical properties. Weight is dependent on gravity, so it can change with location. For example, you would weigh less on the moon than on earth because the gravitational force is weaker on the moon. Mass, on the other hand, is independent of location and depends only on the amount of matter in an object.
What is the metric system?
During the Age of Enlightenment it became apparent that there was need for an entirely new system of weights and measures. This resulted in the creation of a coherent set of units called the metric system (Systeme International d’Unites or SI).
The 7 basic metric units are: meter, kilogram, second, ampere, kelvin, candela and mole. All other metric units are defined by multiplying or dividing these base units.
The metre, kilogram and second are anchored to immutable properties of the universe. The metre is tied to the distance light travels in a fraction of a second, while the kilogram is anchored to a platinum-iridium cylinder in Sevres, France. The meter-tonne-second (MTS) and metre-kilogram-second-coulomb systems (MKS) are extensions of these base units. Several nations, notably the US, use variant spellings of these units to reflect standard English spelling (e.g.’metre’ and ‘litre’). However, these spellings are universally recognised in scientific contexts. ‘Decametre’ and ‘dekametre’ are also acceptable spellings for metric prefixes.
Why is the metric system used all over the world?
The metric system was devised by scientists to meet their needs. As such, it is a logical and exact system. Its base units, such as the meter (equal to one ten-millionth of the distance from the Earth’s equator to the North Pole along a meridian passing through Dunkirk and Barcelona), are derived from natural constants.
The metric system also has few individual units, so it’s easy to learn and understand. Its flexibility allows professionals and scientists to share data without worrying about conversion factors. It is also the standard measurement system for most of the world. In fact, only three countries – the United States, Liberia and Myanmar – do not use the metric system. Even so, products sold in the US often include both customary and metric measurements on their labels and merchandise literature. This is because international supply chains often require metric measurements to be used. Moreover, many companies develop and manufacture products using metric design practices in order to remain competitive globally.
How do I measure mass?
There are many different ways to measure mass. One of the most common is to use a balance. This works because the force exerted on a balance by an object is proportional to its mass. A balance also takes into account the effects of gravity so that objects are weighed the same way regardless of their location on Earth.
Another way to measure mass is to calculate it using the formula Mass = Density x Volume. This is useful for things like comparing the masses of different types of objects, such as a pineapple and a baseball bat.
Finally, it is possible to measure the passive gravitational mass of an object by measuring its acceleration when it falls. This is done by attaching a spring to the object and measuring its oscillations. The force required to keep the object in a falling state is then calculated from its acceleration and its mass. This method is not very practical for everyday applications, but it can be used to determine the mass of things that are too small to be weighed directly.