This sensorial lesson is designed for 3 to 6-year-old children to guide them with the difference in height using Montessori blue knobless cylinders.

In our previous video, we learned about the Montessori yellow knobless cylinder box. It teaches the child how a cylinder’s height and size decrease when placed in a row.

## What are Blue Knobless Cylinders?

The blue knobless cylinders box is a set of 10 blue-colored cylinders and is 4th in the row when introducing Montessori knobless cylinders to the child. In this box, as the height decreases, the diameter remains constant. It is introduced to develop visual discrimination based on the difference in height.

## Purpose of Introducing Blue Knobless Cylinders

• It helps in developing a child’s visual perception of dimension.
• It helps in developing a child’s order and coordination.
• It improves movement and fine motor control.
• It helps the child prepare for more complex topics in mathematics, such as comparison, grading, and seriation, with varying combinations of other 3 knobless cylinders.

## Control of Error

Each cylinder has a different height when seen visually.

## Points of Interest

• The color of the cylinders, i.e. blue.
• The difference in the height of each cylinder.

## How to Present Montessori Blue Knobless Cylinders to the Child?

1. Invite the child to the table while carrying the box of blue knobless cylinders.
2. Take off the box lid and place it below the box.
3. Using your thumb and two primary fingers, slowly remove each cylinder and place them randomly in a row in front of the child.
4. Tell the child “Now, I am going to arrange these cylinders in descending order.”
5. Introduce the child with the tallest and the smallest blue cylinders.
6. Let the child compare their height.
7. Now, place the tallest blue cylinder on the left.
8. Select the next tallest blue cylinder and place it in position 2 (from left to right.)
9. Continue till all the cylinders are placed in order from the tallest to the smallest.
10. Touch the top of each cylinder from left to right and introduce them again with the concept of tall and small.
11. Ask the child, “Do you observe any difference in these cylinders?”
12. Let them reply, “Yes, as we move from left to right, the height of the cylinder is decreasing. They are becoming smaller”.
13. Agree with them and say, “yes, these cylinders are reducing in height as we are moving from left to right.”

Invite the child to arrange the blue cylinders as per the height as shown in the video and help them develop their visual dimension senses.