## The Pink Tower

### MATERIAL:

Ten solid wooden cubes varying in size from 1 cubic centimeter to 1
cubic decimeter. These are pale pink or plain wood. A strong pink must
not be used. If it is used, children are more aware of color than of
size. If in plain, lightly varnished wood, a very good hard wood must
be used.

### PURPOSE:

1) Visual and muscular perception of dimension leading to an abstract
understanding of size
2) Awareness of dimension leading to intelligent observation of size in
the environment
3) Coordination of movement
4) Perfection of hand movements
5) Preparation for mathematics
a) There are 10 cubes because 10 is the basis of our number system
b) The largest cube would hold 1 liter, the smallest 1 cubic centimeter
c) Preparation for cube root
Eight of the smallest make the second cube (23).
Twenty-seven of the smallest make the third cube (33).
Sixty-four of the smallest cube make the fourth cube (43),etc.
One thousand of the smallest cube make the tenth cube (103).

### AGE:

21/2  to 5 years.

### PRESENTATION:

The teacher asks the child to spread a dark green mat on the floor on
which to work. She shows the child how to carry the cubes (two or three
at a time) and place them at random on the mat. The teacher sits beside
the child and builds a tower in order of size starting with the largest
cube. Each cube is placed concentrically on the one before in one
movement. She pauses and looks at the cubes. The child sees that a
deliberate choice is being made. The teacher must not, however, re-
adjust a cube after it has been placed in position as a child may think
this is part of the lesson and copy her movements. Therefore, the
teacher must have worked the tower until she can build it perfectly
before giving the lesson.

The cubes are grasped from above with fingers and thumb on four sides.
In this way, it is possible to judge size by touch as well as by sight.
The child may need to use two hands to put the largest one in position,
but the teacher can grasp them all correctly and the child can grasp
all those he or she can in the same way.

Note:

With developmentally delayed children, every other
cube may be given at first. It does not matter which five the child
works with. The difference between any two cubes in succession will be
twice as great as when using all ten, and the child will have more chance of
succeeding. When the child can manage 5 well, he or she can have the ten cubes.
The child with serious difficulty in motor control, can grade the
pieces in a row rather than building them into a tower until his or her
movements are more controlled.

EXERCISE 1

The child builds the tower as shown. He or she will make mistakes at first, but
will gradually perfect the ability to judge size with practice. The
teacher must not interfere. If the child obviously has not understood the
lesson, then the teacher will give him or her a new lesson another day before
he or she starts using the material. New lessons can also be given to help the
child improve in handling the material.

The tower must not be knocked down as the edges and corners are soon
spoiled when this is done. The child should take it down block by
block.

EXERCISE 2

When the child does Exercise 1 easily and well, he can be shown how to build the tower with one corner of each cube exactly above the other all the way up, with the corner and two faces of the cube exactly flush. There will be two ledges, 1 cm. wide, on the other two sides of the tower. The smallest cube will fit on these ledges. The child is shown to run the cube along each ledge in turn. This exercise demonstrates the relationship in size between the cubes.

### SELF-CORRECTION

Visual:
a) The child can usually see his or her errors when looking at the
completed tower.
b) If the tower is very badly built it will fall over.

### VOCABULARY

Once the child has worked with the material for a while, and is discriminating the differences in dimension, the "Three Period Lesson" can be used to introduce the terminology as appropriate.

cube
large, small
large, larger, largest
small, smaller, smallest