The Story of Measurement
This lesson is best shared as a story or a conversation rather than a formal lecture. The goal is not memorization, but appreciation: helping children value why measurement matters, how it supported human cooperation, and how people used creativity to solve problems of measurement long before rulers and measuring tapes were invented.
You don’t need to memorize every unit. It’s helpful to keep a short list nearby while you tell the story, and to invite children into the experience: compare your hand to theirs, stretch your arms, take a step, and imagine how confusing early measurement must have been when everyone’s body was different.
The Story
No one knows exactly when the first measurements were made. What we do know is that humans have been measuring for a very long time.
At first, people measured using what they always had with them: their bodies. Someone might say, “Your fish is as long as my hand,” or “That piece of wood is two steps long.” These measurements worked until people began trading, building, and needing to agree.
Around 3000 BC, in ancient Egypt, people used a unit that they called “meh” and Ancient Romans later called the cubit. The word comes from the Latin cubitum, meaning elbow. A cubit was the length of a person’s forearm, from the tip of the little finger to the elbow.
As you can imagine, this caused problems. Not everyone had the same forearm length. Disagreements and quarrels became common, especially when people were buying and selling goods.
To solve this, the Pharaoh made an important decision. Everyone would use his cubit, which came to be known as the royal cubit. A stick marked with this length was created, and copies were sent throughout the land so everyone could measure the same way.
But there was a catch. When the Pharaoh died and a new ruler took his place, a new royal cubit was introduced. New sticks were made. Measurements shifted again.
People also noticed another problem: some things were smaller than a cubit. New units were needed.
They introduced the hand, the width of a hand at the base of the fingers. A hand was about five fingers wide. Today, a hand is defined as four inches and is still used to measure horses from the ground to the horse’s withers (its shoulder), since a horse won’t hold its head still.
Hands were divided into fingers, and people noticed patterns:
About seven hands made one cubit
A pace equaled two cubits
The royal foot equaled 18 fingers
Other cultures developed their own systems.
The ancient Hebrews used a span—the distance from the thumb to the outstretched little finger.
The Greeks combined Egyptian and Hebrew ideas and expanded them using multiples of fingers.
The Romans also relied on the body:
An uncia (where the word inch comes from) was the width of a thumb
12 uncia = 1 foot
3 feet = 1 yard
A yard was sometimes described as the distance from a person’s nose to the tip of an outstretched middle finger.
In England, the yard became more formally defined. In the 12th century, King Henry I fixed the yard as the distance from his nose to the thumb of his outstretched arm. Today, a yard is 36 inches.
In the 14th century, King Edward II ruled that one inch equaled three grains of barley laid end to end.
By 1855, the length of the yard was agreed upon across Europe. From then on, other measurements were derived from it:
12 inches = 1 foot
3 feet = 1 yard
1,760 yards = 1 mile
The word mile comes from the Latin milliare, meaning a thousand paces—the distance marched by a Roman army.
Measuring Water and the Sea
Some measurements were developed specifically for water and navigation.
A fathom equals 6 feet and has been used in England since before 1600 to measure the depth of water. The word comes from the Anglo-Saxon faethm, meaning to embrace, because it’s roughly the distance from one hand to the other with arms outstretched.
6 feet = 1 fathom
15 fathoms = 1 shackle
A cable equals 608 feet, and 10 cables equal one nautical mile.
A nautical mile is 6,080 feet and measures ocean distances. It represents one minute of arc on the Earth’s surface.
Body-Based Measurements (At a Glance)
Many traditional units came directly from the human body:
Foot: 12 inches
Hand: 4 inches (used to measure horses)
Palm: 3 inches (likely the width of the hand without the thumb)
Nail: 16 nails = 1 yard (a cloth measure; each nail was about 2¼ inches)
Finger: 8 fingers = 1 yard (another cloth measure)
Today, the measurements we use are no longer based on the body, but they carry the story of the body with them.
Follow-Up Activity
Walk around your home and measure everyday objects using different body parts:
Hands
Feet
Fingers
Arm spans
Paces
Children may enjoy recording their measurements or comparing how results differ between people. This naturally leads to rich discussions about accuracy, fairness, and why standardized measurement matters.
Book Suggestions
These pair beautifully with the story and help children visualize the challenges and creativity behind early measurement.
You’ll find many more stories like this — plus authentic Montessori hands-on lessons and follow-up activities — inside the Elementary Timeline Curriculum.
