Chapter VII – Comparing Sizes
Table of Contents:
- 1. Small, Bigger, Biggest Circle
- 2. Cylinder Towers – Who Will Build the Tallest?
- 3. Who Has the Bigger Block?
- 4. Comparing the Length of Caterpillars
- 5. Bridges of Different Lengths
- 6. Towers of Colors and Sizes
- 7. Length Races – The Road to the Finish Line
- 8. Guess Which One Is Longer!
- 9. Bridges over the Abyss – Who Will Build the Longer One?
- 10. Block Order – Arrange from Smallest to Largest
- 11. Platform Stairs
- 12. Small Inside, Big Outside
Comparing Sizes
The chapter “Comparing Sizes” introduces children to the fascinating world of observing, analyzing, and organizing objects around them according to their size. Through play with Korbo blocks—cylinders, gear wheels, and platforms, stacking and connecting them—children learn to notice and compare dimensions such as long–short, tall–short, big–small, bigger–smaller, thick–thin.
In the proposed activities, preschoolers manipulate concrete objects, arrange them in order, build structures, and make their first attempts at classifying and estimating “by eye” and using simple references (for example, their own hand or the number of elements). In this way, they develop mathematical skills in a natural, sensory, and engaging manner—through action, building, and experimentation.
These activities are an important stage in preparing children for further mathematical skills such as measuring, estimating, counting, and analyzing relationships between sizes. Working with Korbo blocks allows children to experience these concepts in a practical and tangible way, which is especially important at the preschool education stage.
After completing the set of activities and tasks in this chapter, the child:
Recognizes and names basic size-related concepts such as big-small, bigger-smaller, tall-short, long-short, wide-narrow.
Compares two or more objects in terms of size, describing differences verbally (“This one is taller,” “That one is smaller”).
Arranges objects in order according to one feature (for example, from largest to smallest, from shortest to longest).
Matches elements into pairs of the same size (for example, two identical gear wheels).
Experiments with building structures of different heights, lengths, and widths, analyzing their size based on the number of blocks used.
Makes simple comparative measurements, such as checking which tower is taller, which bridge is longer, or which cylinder rolls farther.
Uses mathematical vocabulary in everyday speech during play (for example, “my road is longer,” “this wheel is bigger”).
Understands the relationship between size and function (for example, a shorter bridge does not reach the edge of the table).
Develops spatial orientation and logical thinking through constructing and analyzing differences in structures.
Cooperates with peers while completing tasks, sharing materials and jointly comparing the results of their work.
1. Small, Bigger, Biggest Circle
Objective: Developing the ability to compare the sizes of elements.
Materials Needed:
Gear wheels, platforms, cylinders, straight connectors
Procedure:
Children receive one element of each type of block (connector, cylinder, wheel, platform).
They arrange them from the smallest to the largest.
They name the elements and compare them, saying for example: “This one is bigger/smaller than…”
Additional Challenge:
Close your eyes and recognize the size of the wheel using touch only.
2. Cylinder Towers – Who Will Build the Taller One?
Objective: Comparing the height of constructions.
Materials Needed:
Cylinders, platforms, connectors
Procedure:
Children build towers using cylinders and connectors and place them on platforms.
They compare the towers by asking: “Whose tower is taller?” “Which one is shorter?”
They measure the towers using their hand or a ruler.
Additional Challenge:
Build a tower with your eyes closed, counting the cylinders and connectors as you go.
3. Who Has the Bigger Block?
Objective: Comparing and identifying differences.
Materials Needed:
Gear wheels, connectors, cylinders, platforms, small bags from the Korbo Maluch set
Procedure:
Two children each draw one block from a bag.
They compare them by asking: “Which one is bigger?” “Which one is smaller?”
Additional Challenge:
Children draw two elements each, place them next to each other side by side, and compare which arrangement of two blocks is longer.
4. Comparing the Length of Caterpillars
Objective: Comparing length through building and measuring.
Materials Needed:
Cylinders, connectors
Procedure:
Each child builds a single-color “caterpillar” from cylinders (for example, blue ones) and connectors.
Allow the children to build for a set amount of time, for example 2 minutes or 5 minutes.
Then they compare the lengths of their constructions.
Additional Challenges:
Build two caterpillars of the same length using a different number of cylinders (once using straight connectors and once using cross connectors).
Join the caterpillars into one long caterpillar and check together with the whole class how long it is (the unit of measurement can be, for example, tip-toe steps-small steps, foot to foot).
5. Bridges of Different Lengths
Objective: Recognizing differences in length and height.
Materials Needed:
Platforms, cylinders, cross connectors
Procedure:
Children build bridges from platforms connected with cylinders.
They place the bridges between tables.
Then they compare them by asking which one is longer and which one is higher.
Additional Challenges:
Build a bridge that can support the weight of a small vehicle built from Korbo blocks.
Place the bridges on the floor in order from the shortest to the longest.
6. Towers of Colors and Sizes
Objective: Classification by two features: color and size.
Materials Needed:
Cylinders and gear wheels in different colors
Procedure:
Children build towers using gear wheels of the same color, with some towers made of larger elements and others of smaller ones (for example, a large blue tower, a small red one, etc.).
Then they compare them by asking: “Which colored tower is the tallest?” “Which one has the largest wheel on top?”
Additional Challenges:
Arrange the towers from the largest to the smallest wheel, changing the colors.
Timed task: who can build a tower with the same number of blocks faster—one tower made of gear wheels, the other made of cylinders connected with connectors?
7. Length Races – The Road to the Finish Line
Objective: Spatial comparison of length and distance.
Materials Needed:
Platforms connected in a line (placed next to each other) or cylinders connected with connectors.
Procedure:
Children build “roads” made of a smaller or larger number of blocks (as indicated by the teacher).
Then they measure the roads and compare them with others, deciding which road is the shortest and which is the longest.
Additional Challenges:
Children connect all constructions together, trying to link two distant points in the room using one road. They check the length of the road using elbows, tiptoe steps, regular steps, etc.
Children build a road with turns and then try to lay it out “flat” to compare its length.
8. Guess Which One Is Longer!
Objective: Developing the ability to estimate and compare lengths.
Materials Needed:
Cylinders, connectors, gear wheels
Procedure:
The teacher prepares several sets with different quantities, for example:
sets of gear wheels (number chosen by the teacher),
sets of connectors and cylinders (both elements in the same quantity), for example one set with 11 elements each, another with 8, etc.
Children look at the sets of elements and estimate which group will allow them to build the tallest structure.
Then they build the constructions and place them next to each other to compare.
Additional Challenges:
Build three constructions and arrange them in order from the shortest to the longest.
Add an extra set of platforms (in this case there may be fewer elements, but the structure may become taller).
9. Bridges over the Abyss – Who Will Build the Longer One?
Objective: Comparing the length of bridge constructions and estimating
Materials Needed:
Platforms, cylinders, cross connectors, tables in the classroom
Procedure:
The teacher divides the children into groups and places the tables at different distances from each other (for example, 30 cm, 50 cm, 70 cm).
The teacher explains that the spaces between the tables represent an abyss and that the task is to build a bridge over it between two “rocks” (the tables).
Each group first estimates how many blocks will be needed to build the bridge and then builds it.
Next, the children compare the lengths of the completed bridges and check how many elements were used, comparing the results with their initial estimates.
Additional Challenges:
The bridge must be stable enough for a Korbo vehicle to drive across it.
Build two bridges: one using short connectors and one using long connectors, then compare which one required more elements.
10. Block Order – Arrange from Smallest to Largest
Objective: Ordering elements by size.
Materials Needed:
Wheels, cylinders, platforms, straight and cross connectors, cranks
Procedure:
Children receive a set of 5 elements of different sizes.
They arrange them in order from the smallest to the largest or from the lowest to the highest.
Additional Challenges:
The teacher decides how the individual elements are positioned (for example, a wheel may lie flat or stand upright).
Reverse the order, arranging the elements from the largest to the smallest.
11. Platform Stairs
Objective: Building a stepped structure and comparing heights.
Materials Needed:
Platforms, cylinders (in different quantities)
Procedure:
Using cylinders and cross connectors, children work in groups to build stairs.
Then they compare them by asking: “Which step is the highest?” “Which one is the lowest?”
Additional Challenges:
A small figure walks up the stairs and counts the steps. It can also walk down (counting backward).
Add construction conditions, for example: the first step is blue, the fourth and sixth are red.
12. Small Inside, Big Outside
Objective: Constructing using different sizes and positioning elements by size.
Materials Needed:
Korbo blocks
Procedure:
Children work together to build a large circle on the floor by placing cylinders next to each other.
Next, inside the circle they build a square from gear wheels.
Inside that, they place for example a triangle built from connectors, and even further inside, for example, a square or rectangle made from platforms.
Then the children discuss with the teacher:
Which shape is the largest and which is the smallest?
How many blocks were used to build each shape?
Which colors were used and how many blocks of each color?
Additional Challenges:
The teacher changes the task, for example:
“Inside a large circle made of gear wheels, build two rectangles from cylinders. In one rectangle, build a circle from connectors, and in the other, build a square from four platforms.”