The metric system is a standardized system which is used to determine weights and measures. It was invented in 1795 by two French scientists. This explains why it is often abbreviated to “SI” or “SI System”, which stands for Système Internationale (the French translation for International System).
Today, the metric system is the primary system of measurement in most countries in the world. The reason it has been adopted by so many countries is because it is a decimal system.
In a decimal system, when you move a number’s decimal point (or ‘period’) one place to the right or left, you multiply or divide that number by ten. Compared to imperial measurements, metric units are much easier to understand because they make more sense. For example, one kilometer equals one thousand meters and one kilogram equals one thousand grams. This is compared to one foot which equals 12 inches and one yard which equals three feet. The metric system has standardized prefixes that are easy to remember and take away the need for extra units.
You may already know that the metric system is used universally by the scientific community, no matter which country they’re conducting their work in. But you might be wondering why this is.
Scientists who work in different countries need the same system of measurement so they can quickly and easily communicate, understand and compare theories, experiments, ideas and data with one another.
Without a standardized system, they would have to convert units of measurement between different systems, which would be a waste of time and increase the risk of inaccuracies. The metric system was chosen because the conversions between metric units make sense and the majority of countries in the world use it.
Continue reading to find out the answers to some of the other questions surrounding this topic.
Why is measurement important in science?
From chemistry, biology and physics to geology, technology and engineering, the discipline of science is vital for understanding humans and the universe we live in.
But bad equipment, human error and poor data processing can lead to inaccurate results that produce a false understanding.
So scientific measurements must be accurate and precise in order to produce conclusive evidence.
What’s the difference between the metric system and the imperial system?
The metric system and the imperial system use different units of measurement. The units each one uses are listed in the subsections below.
As mentioned earlier, metric units can be converted easily because all you have to do is divide or multiply by ten, whereas converting imperial units is not as straightforward.
The metric system
The metric system is based on the meter as the unit to measure length, the kilogram as the unit for mass and the second as the unit for time.
Some of the other units of measurement used in the metric system are:
- Ampere
- Candela
- Celsius
- Kelvin
- Mole
The imperial system
There are two types of imperial systems: The British Imperial System and the United States Customary System.
The British Imperial System was the official measurement system in the United Kingdom from 1824 to 1965. Before it was introduced, there were multiple local measurement systems, whereby units like pound and foot meant something different, depending on where you were. So, the British Imperial System was developed to unite the country by having one standardised way of measuring.
The United States Customary System is based on British imperial units, but there are some differences between the two. For example, the British stone is not used in the US, a US liquid pint is 0.473 cubic decimeter, a US dry pint is 0.551 cubic decimeter and the US gallon is based on a 231-cubic-inch wine gallon.
Some of the units of measurement used in the imperial system are:
- Fahrenheit
- Foot
- Gallon
- Inch
- Mile
- Ounce
- Pint
- Pound
- Quart
- Stone
- Ton
- Yard
There are only three countries in the world that use imperial units rather than metric units as their primary system of measurement. These are:
- The US
- Liberia
- Myanmar
What are the seven basic units of measurement?
The metric system has seven units of measurement that can be divided or multiplied by ten. These are known as the seven basic units of measurement and are as follows:
- Length — Kilometers (km), meters (m), centimeters (cm)
- Mass — Kilograms (kg), grams (g), liters (l)
- Time — Seconds (s), hertz (hz)
- Amount of substance — Mole (mol)
- Electric current — Ampere (A/amp)
- Temperature — Kelvin (K), Celsius (C)
- Luminous intensity — Candela (cd)
What are the benefits of the metric system?
As already stated, the main benefits of using the metric system are that it is easy to understand and convert and it is used the world over.
Some of the other advantages of using the metric system rather than the imperial system are:
- The metric system is a decimal system, so calculations can be displayed on automatic calculators
- Fractions can be expressed in decimal form, and vice-versa
- There are only around 30 individual units, many of which are only used in specialized fields (and can be expressed in terms of the most common units, for example, the newton (kg-m/s2))
- Unlike the outdated imperial system, it isn’t based on the body parts of people from centuries ago
Why doesn’t the US use the metric system?
The US hasn’t switched over to the metric system as its primary system of measurement mainly because of time and money. The imperial system has been used in manufacturing plants since the beginning of the Industrial Revolution. The machinery used in them was developed to measure in imperial units and products were made to feature them. To change over to the metric system would be expensive and time-consuming. Another argument is that the US should keep the imperial system to set it apart from other countries and symbolize its status as a leader, not a follower.
Having said that, US laboratories use the metric system almost exclusively, when it comes to international trade, the US government considers it the preferred system, and it is taught in schools alongside the imperial system. Also, many measurement tools and commercial products now show the measurements for both systems.
What are the metric to imperial conversions?
Because the imperial system is mainly used in the US, you may be struggling to imagine some of the metric measurements. So, to help you put them into perspective, here are some typical metric-to-imperial conversions:
| Metric unit | Imperial unit |
| 1 liter | 33.814 ounces |
| 3.785 liters | 1 gallon |
| 29.573 milliliters | 1 ounce |
| 0.473 liters | 1 pint |
| 0.946 liters | 1 quart |
| 0.454 kilogram | 1 pound |
| 1 kilogram | 2.2 pounds |
| 1 gram | 0.035 ounces |
| 28.350 grams | 1 ounce |
| 0.907 metric ton | 1 short ton |
| 0.405 hectare | 1 acre |
| 0.093 square meter | 1 square foot |
| 2.590 square kilometers | 1 square mile |
| 30.48 centimeters | 1 foot |
| 1 centimeter | 0.39 inches |
| 2.54 centimeters | 1 inch |
| 1.609 kilometers | 1 mile |
| 0.9144 meter | 1 yard |
| 1 meter | 39.37 inches |
| 130 degrees Celsius | 250 degrees Fahrenheit |
| 150 degrees Celsius | 300 degrees Fahrenheit |
| 190 degrees Celsius | 375 degrees Fahrenheit |
| 200 degrees Celsius | 400 degrees Fahrenheit |
| 230 degrees Celsius | 450 degrees Fahrenheit |
Summary
The discipline of science is vital for understanding humans and the universe we live in. This means scientific measurements must be accurate and precise in order to produce conclusive evidence. The metric system is used universally by the scientific community, no matter which country they are working in.
Scientists in different countries need the same system of measurement so they can quickly and easily communicate, understand and compare theories, experiments, ideas and data with one another.
Without a standardized system, they would have to convert units of measurement, which would be a waste of time and increase the risk of inaccuracies.
The metric system was chosen because the conversions between metric units make sense and the majority of countries in the world use it. While the US uses imperial units as its primary system of measurement, US laboratories use the metric system almost exclusively.
