Montessori AMI Primary Guide
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Three Period Lesson
Memory Games
Visual Sense
  Cylinder Blocks
  Pink Tower
  Brown Stairs
  Red Rods
  Color Tablets
  Geometric Cabinet
  Constructive Triangles
    Rectangular Triangles
    Blue Rectangular Box
    Triangular Box
    Large Hexagonal Box
    Small Hexagonal Box
  Geometrical Figures
  Sensorial Decanomial
  Knobless Cylinders
  Binomial Cube
  Trinomial Cube
  Leaf Cabinet
Tactile Sense
  Sensitizing Fingertips
  Touch Boards
  Touch Tablets
Baric Sense
  Baric Tablets
Thermic Sense
  Thermic Bottles
  Thermic Tablets
Auditory Sense
  Sound Boxes
Olfactory Sense
  Smelling Jars
Gustatory Sense
  Tasting Bottles
Stereognostic Sense
  Geometric Solids
  Sorting Trays
  Mystery Bag
  Sandpaper Globe
  Painted Globe
  Puzzle Maps
    The World
    The Continents
    The Country

Brown Stairs


- 10 brown prisms of the same length (20cm) but differing in height. They vary from 10cm x 10cm x 20cm to 1cm x 1cm x 20cm.
- A floor mat of contrasting color.



Invite the child by telling him you have something to show him.  Tell the child that for this lesson, we will need a mat. Have the child fetch and unroll a mat. Bring him over to the correct shelves and point to the Brown Stairs. Tell the child: “These are the Brown Stairs”. 

- Show the child how to hold the thinnest prism by gripping  over the top of the center part of the prism using your right thumb and fingers.
- Slowly slide the prism off of the shelves until it is fully out.
- Carry the prism vertical and at waist level.
- Have the child carry all of the prisms over one at a time and place them randomly on the right side of the mat. (Show the child to place his hand underneath some of the thicker prisms.)
- Once all of the prisms have been brought over to the mat, have the child stand to your left.
- As you remain standing, carefully pick up the thickest prism (using both hands), and place it near the back left corner of the mat.
- Turn to the child and tell him that you are now looking for a specific one.
- Go over to the right half of the mat and carefully choose the next thickest prism. (Use both hands)
- In a steady and precise movement, place the prism directly under the thickest prism and align them so that they are well aligned.
- Once it has been placed, check to see if it is well aligned by sliding your hand along the left side of the two prisms.  
- Continue placing all of the prisms in correct order and placing them so they come closer and closer to you as each is placed.

Dismantle the Brown Stairs by removing the thinnest to the thickest prism and placing them on the right half of the mat.

Invite the child to build the Brown Stairs. To help him get started, ask him which one he is going to start with. If the child seems to understand, you can let him work alone. Once he is done, have him replace the prisms in correct order on the shelves.


Exercise 1
The child builds the stairs individually as was shown in the demonstration.

Exercise 2
Once the child has seemed to master the building of the stairs, the directress will show him an additional step. The directress will carefully place the thinnest prism on the ledge of the second thickest prism and up against the thickest prism. Show the child that by doing so, the second thickest prism is now at the same height as the thickest. Repeat this on every edge of every prism by working your way down.

Grading from an extreme
Grading from a midpoint
Matching to the environment           

Thick and Thin
The positives, comparatives, and the superlatives


Direct Visual discrimination of dimensions (thickness).

- Refinement of voluntary movement.
- Muscular education of grip.
- Preparation for mathematics.

Control of Error
The control of error lies within the child being able to discriminate the dimensions.

3 to 3 1/2 years           

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