E. Spatial Sense · Shapes, Position and Measurement

Measuring by Comparing: Length and Area

E2.1 E2.2About 30 minutes

Learning goals

I can tell what can be measured about an object: its length, its area, its mass and its capacity.
I can compare the length of objects by lining them up from the same starting line.
I can order 3 or more objects from shortest to longest.
I can compare area by putting one thing on top of the other.

Words to know

measure
To find out how big, long, heavy or full something is.

attribute
Something about an object we can measure or describe, like how long it is.

length
How long something is, from one end to the other. Height is length going up.

area
How much flat space a surface covers, like how much of the table a placemat covers.

mass
How heavy something is.

capacity
How much something can hold inside, like how much water a cup holds.

direct comparison
Putting two things right next to each other (or on top of each other) to see which is bigger.

longer / shorter / taller
Words to compare length and height.

order
To put things in a row from smallest to biggest, or biggest to smallest.

Who is taller, you or your grown-up? Which hockey stick is longer? Which blanket covers more of the bed? These are all measuring questions! Today we learn what we can measure, and how to compare things fairly.

What can we measure?

Every object has different things we can measure. These are called measurable attributes.

Attribute	Question it answers	Words we use
length (and height)	How long? How tall?	longer, shorter, taller, the same length
area	How much flat space does it cover?	covers more, covers less, bigger, smaller
mass	How heavy?	heavier, lighter, the same mass
capacity	How much can it hold?	holds more, holds less, full, empty

Four things we can measure.

Worked example

What can we measure about a juice box?

Name the attributes you could measure about a juice box.

Length: How tall is it? How wide is it?
Area: How much of the table does its bottom cover? How big is its front?
Mass: How heavy is it? (It is heavier when full!)
Capacity: How much juice can it hold?

We can measure its length (height), area, mass and capacity.

Comparing length

To compare lengths fairly, line up the ends on the same starting line. Then look at the other end. The one that sticks out farther is longer.

Three ribbons lined up at the start line. Ribbon C is the longest. Ribbon B is the shortest.

Worked example

Order the ribbons

Put ribbons A, B and C in order from shortest to longest.

Check that all three start at the same line. They do.
Look at the other ends. B stops first, so B is the shortest.
C goes the farthest, so C is the longest.
A is in the middle: longer than B but shorter than C.

Shortest to longest: B, A, C.

Fair comparing

If the ends are not lined up, you cannot tell which one is longer just by looking. Always start from the same line, like runners at the start of a race!

Ribbon E looks like it goes farther to the right, but it starts later. Line them up first!

Length stays the same

If you bend a string or make it wiggly, it is still the same string. Its length did not change, even if it now looks shorter. To compare, straighten it out first.

A straight string and the same string bent into a wiggle. Same length!

Comparing area

Area is how much flat space something covers. To compare area, put one thing on top of the other. If one fits inside the other with space left over, the bottom one has the greater area.

The book fits on top of the placemat with space left over. The placemat has a greater area than the book.

Worked example

Which covers more?

Does a sheet of paper or a sticky note have a greater area?

Line up one corner of the sticky note with one corner of the paper.
Lay the sticky note on top of the paper.
The sticky note fits inside the paper, and lots of paper is still showing.

The sheet of paper has the greater area. The sticky note has the smaller area.

Challenge

Sometimes one shape does not fit inside the other, because one is longer and the other is wider. Then you can cut one up and move the pieces, or cover both with the same small things (like crackers or sticky notes) and count. Try it as a challenge!

Just for fun

Riddle: What gets bigger the more you take away from it?

A hole!

Hands-on activity

Measuring detectives

Length hunt: cut a piece of string or ribbon as long as your arm. Find 3 things that are longer than your string, 3 things that are shorter, and 1 thing that is about the same.
Line-up: collect 4 objects, such as a crayon, a spoon, a toothbrush and a shoe. Line them up on the edge of a table and order them from shortest to longest.
Family height line: stand back to back with family members (no shoes, heels on the floor). Order everyone from shortest to tallest.
Area test: compare a placemat, a book, a napkin and a sheet of paper by laying them on top of each other. Which covers the most? Which covers the least?

Your turn!

Name the 4 attributes we can measure that you learned today.

In the ribbon picture, which ribbon is longest?

Why must you line up the ends when comparing length?

A pencil and a crayon are lined up at the same start line. The pencil sticks out farther. Which is shorter?

Order from shortest to tallest: a giraffe, a cat, a horse.

A sticky note fits on a book with space left over. Which has the greater area?

You coil a skipping rope into a circle. Did its length change?

Which question is about area: "How heavy is it?" or "How much of the table does it cover?"

More practice: warm-up

Which attribute tells how heavy something is: length, area, mass or capacity?

True or false: a hockey stick is longer than a pencil.

Fill in the blank: to compare lengths fairly, line up the ends at the same ___ line.

Which is usually taller: you or a door?

Which has the greater area: a bedsheet or a face cloth?

More practice: on your own

These trains all start at the same line. Order them from shortest to longest.

Train A: 🚃🚃🚃
Train B: 🚃🚃🚃🚃🚃
Train C: 🚃🚃🚃🚃

Jen is taller than Max. Max is taller than Ali. Who is the tallest? Who is the shortest?

"How much water can a pail hold?" Which attribute is this question about?

A napkin fits on top of a placemat with space left over. Which has the smaller area? How do you know?

Mia has a long, thin ribbon and a square napkin. She says, "The ribbon is longer, so it covers more." Can she be sure?

Challenge

Find the mistake! Owen puts a blue crayon at the edge of the table. He puts a red crayon starting farther in from the edge. The red crayon sticks out farther, so he says red is longer. What should he do?

A pencil is longer than an eraser. A ruler is longer than the pencil. A skipping rope is longer than the ruler. Order all four from shortest to longest.

Lia covers a book with sticky notes and needs 6 notes. She covers a placemat with the same kind of sticky notes and needs 9. Which has the greater area? How do you know?

Check your understanding

Quiz

How should you compare the lengths of two pencils?

Three straws are lined up at a start line. Straw X ends first, then straw Y, then straw Z ends farthest. Which order is shortest to longest?

A placemat covers more of the table than a coaster. Which has the greater area?

Which word tells how much something can hold?

You make a straight shoelace curvy. Is it now shorter?

Which question is about length?

Order from shortest to longest: a crayon, a hockey stick, a spoon.

For parents and teachers

What your child is learning: naming measurable attributes (length, area, mass, capacity) and comparing and ordering objects by length and area using direct comparison, meaning putting objects side by side or on top of each other without rulers (Ontario Grade 1, E2.1 and E2.2). Standard units like centimetres come later.

Common mistakes:

Not lining up the ends. Many children just look at which end sticks out farther. Use a table edge as a start line.
Thinking a bent or coiled object is shorter. Straighten it together and compare again.
Mixing up area with length ("it is longer, so it is bigger"). A long thin ribbon can cover less area than a square napkin. Lay them on top of each other to check.

How to help: use comparing words daily: "Is your scarf longer or shorter than mine?" "Which towel covers more of the floor?" Ask your child to explain how they know, and to make their comparison fair. Celebrate careful checking.