Units of Measurement Lesson: Definition, Types, Chart and Examples

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Updated: Dec 30, 2024

Lesson

Lesson Overview

What Is a Unit of Measurement?
Units of Measurement Chart
Types of Units of Measurement
The International System of Units (SI)
The United States Customary System (USCS)
Unit of Measurement Examples

Units of measurement are standard quantities used to express the length, weight, capacity, or distance of objects. For example, length is measured in meters, weight in kilograms, and distance in kilometers.

Units ensure accuracy and consistency, allowing to compare and communicate measurements clearly in everyday life

What Is a Unit of Measurement?

A unit of measurement is a definite magnitude of a quantity, defined and adopted by convention or law, that serves as a standard for measuring the same kind of quantity. Essentially, it's a standardized "amount" of something.

Example:

Meter: A unit of length. Fabric for clothing is often measured in meters.
Kilogram: A unit of mass. A sack of rice may weigh 5 kilograms.
Liter: A unit of volume. Milk is typically sold in 1-liter cartons.
Second: A unit of time. It takes about 60 seconds to boil water in a microwave.

Celsius: A unit of temperature. Room temperature is generally around 25°C.

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Units of Measurement Quiz

Units of Measurement Chart

This chart provides a handy overview of common units used to measure various quantities:

Quantity	Units of Measurement	Examples
Length	Meter, Kilometer, Centimeter, Millimeter, Foot, Yard, Inch, Mile, Nautical Mile	A door is about 2 meters tall; a marathon is 42 kilometers.
Mass	Gram, Milligram, Kilogram, Ounce, Pound, Metric Ton, Imperial Ton	A loaf of bread weighs about 500 grams; a car weighs 1.5 tons.
Volume	Liter, Milliliter, Kiloliter, Gallon, Pint, Fluid Ounce, Cubic Meter	A water bottle holds 500 milliliters; a swimming pool holds 50,000 liters.
Time	Second, Minute, Hour, Day, Week, Month, Year	A movie lasts about 2 hours; a year has 365 days.
Temperature	Kelvin, Celsius, Fahrenheit	Water freezes at 0°C (Celsius) or 32°F (Fahrenheit).

Types of Units of Measurement

Units of measurement are classified according to the physical quantities they represent, such as length, mass, time, temperature, and volume.

Each category includes different units that are used to measure specific aspects of these quantities in various contexts.

Units of Measurement for Length

Length measures how long or wide an object is. It can refer to distance, height, or size. The most commonly used units of length include both metric and imperial systems.

System	Units of Measurement	Conversion
Metric Units	Centimeter (cm)	1 cm = 10 mm
	Meter (m)	1 m = 100 cm
	Kilometer (km)	1 km = 1000 m
	Millimeter (mm)	1 mm = 0.001 m
Imperial Units	Foot (ft)	1 foot = 12 inches
	Inch (in)	1 inch = 0.0833 foot
	Mile	1 mile = 5280 feet
	Yard	1 yard = 3 feet = 36 in

Units of Measurement for Mass

Mass measures the amount of matter in an object. Common units for mass include grams, kilograms, pounds, and ounces. These units help quantify how heavy or light an object is.

System	Units of Measurement	Conversion
Metric Units	Milligram (mg)	1 mg = 0.001 g
	Gram (g)	1 g = 1000 mg
	Kilogram (kg)	1 kg = 1000 g
Imperial Units	Ounce (oz)	1 oz = 0.0625 lb
	Pound (lb)	1 lb = 16 oz
	Ton	1 ton = 2000 lbs

3. Units of Measurement for Time

Time measures the duration of events or processes. We commonly measure time in seconds, minutes, hours, and days. These units are universally standard across different systems.

Units of Measurement	Conversion
Second (s)	1 s = 1/60 min
Minute (min)	1 min = 60 s
Hour (hr)	1 hr = 60 min = 3600 s
Day	1 day = 24 hr
Week	1 week = 7 days
Month	1 month = 4 weeks
Year	1 year = 12 months

4. Units of Measurement for Temperature

Temperature indicates how hot or cold an object is. The units used for temperature include Celsius, Kelvin, and Fahrenheit. Kelvin is the SI unit for temperature, while Celsius and Fahrenheit are more commonly used in daily life.

Units of Measurement	Conversion
Celsius (°C)	0°C = 273.15 K = 32°F
Kelvin (K)	0 K = -273.15°C = -459.57°F
Fahrenheit (°F)	0°F = -17.778°C = 255.372 K

5. Units of Measurement for Volume

Volume measures the amount of space an object occupies. The SI unit of volume is the liter (L). Common imperial units for volume include gallon, pint, and fluid ounce.

System	Units of Measurement	Conversion
Metric Units	Milliliter (ml)	1 ml = 0.001 L
	Liter (L)	1 L = 1000 ml
	Kiloliter (kl)	1 kl = 1000 L
	Cubic Centimeter (cm³)	1 L = 1000 cm³
Imperial Units	Fluid Ounce (fl. oz.)	1 fl. oz. = 1/20 pt
	Gallon (gal)	1 gal = 128 fl. oz.
	Pint (pt)	1 pt = 16 fl. oz.

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Test Your Units and Measurements Knowledge With the Trivia Quiz

Key Takeaways

Units of measurement provide a standardized way to express physical quantities like length, mass, and temperature.
Different systems of measurement exist, with the metric and imperial systems being the most common.
Historically, measurement units were often based on human body parts, highlighting the evolution towards standardized systems.

The International System of Units (SI)

The International System of Units (SI), also known as the metric system, provides a globally recognized standard for measurement. Each SI unit represents a specific physical quantity with a precisely defined magnitude.

Physical Quantity	SI Unit of Measurement	Symbol
Length	Meter	m
Mass	Kilogram	kg
Temperature	Kelvin	K
Time	Second	s
Capacity/Volume	Liter	L
Electric Current	Ampere	A
Amount of Substance	Mole	mol

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SI Units Trivia Quiz

The United States Customary System (USCS)

The United States Customary System (USCS) is a set of measurement units based on the British imperial system. It's still commonly used in everyday life in the U.S. Here's a breakdown:

Length: Inches, Feet, Yards, Miles
Weight: Pounds, Ounces
Volume: Gallons, Quarts, Pints, Cups

Notably, US gallons differ from imperial gallons. While USCS is common, metric units like centimeters and liters are preferred in science, medicine, and industry.