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Hidden Letters

Stem Activities

Ages: 3-5

30 minutes

Grownup needed

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Here's a fantastic way to help young children learn letters! It makes learning the alphabet as fun as a game while incorporating STEAM scientific knowledge, sparking young scientists' curiosity and desire to explore.

Materials Needed

Cardboard
White paper
Scissors
Ruler
Tape
Pencil
Red
Yellow and blue markers
Resealable plastic bag

An assortment of craft supplies lies arranged on a light wood-grain table. These supplies include a piece of folded cardboard, a blank sheet of white paper, black scissors, a clear plastic bag or sheet with textured wrinkles, a blue pencil, three white marker pens with red, blue, and yellow caps, a roll of yellow tape, and a clear plastic ruler. This image suggests the preparation for a craft or DIY project.

Step-by-step tutorial

Step 1

Draw a 9cm diameter circle on the cardboard, and as shown in the diagram, draw a 7cm×3cm rectangle below the circle - this will be your colour filter. Cut out the drawn filter with scissors.

Two hands are cutting a piece of cardboard on a light wood-grain table. A circle and a connected rectangle have been drawn on the cardboard, resembling a lollipop or paddle shape. The rectangle has 7cm written along its length and 3cm written along its shorter base. Black scissors held in the right hand are cutting along the bottom edge of the rectangular shape. This image appears to be a step in a craft or DIY project.

Step 2

Draw a 5.5cm square in the middle of your cut-out filter, then carefully cut out the square. Take care not to hurt yourself.

A lollipop-shaped piece of cardboard rests on a light wood-grain table. A square is drawn within the circular top part of the shape, with the notation 5.5cm above it, indicating the square's side length. This cardboard cutout likely serves as a template or component in a craft or DIY project.

Step 3

Take your plastic bag, use a ruler and pencil to draw a 6cm square, then cut it out with scissors.

Two hands are shown cutting a clear plastic bag or sheet on a light wood-grain table. The left hand holds the plastic flat while the right hand uses black scissors to cut along one edge. The plastic appears to be a resealable bag, as a zip-top closure is visible along the top edge. This image likely depicts a step in a craft or DIY project.

Step 4

Use tape to attach the transparent square to your filter as shown in the diagram.

Two hands hold a circular piece of cardboard with a rectangular window cut into it on a light wood-grain table. The cardboard is covered with yellow tape, and a piece of clear plastic is affixed over the window, creating a transparent viewing area. The hands are holding the edges of the cardboard, likely demonstrating a stage in a craft or DIY project.

Step 5

Now use your red marker to colour the filter lens!

Two hands are working with a lollipop-shaped piece of cardboard on a light wood-grain table. The circular part of the cardboard has a square window covered with a piece of clear plastic. The right hand holds a white marker with a pink cap and is coloring the plastic red. The left hand holds the cardboard steady. This image likely shows a step in creating a homemade color filter or a similar craft project.

Step 6

Write different letters on the white paper using the blue marker.

On a light wood-grain table, two hands interact with a white sheet of paper. The paper has various uppercase and lowercase letters written on it in blue ink, scattered seemingly randomly across the surface. The right hand holds a white marker with a light blue cap and is in the process of writing on the paper. The left hand rests on the bottom left corner of the paper. The scene suggests an activity involving writing, perhaps a word game or a learning exercise.

Step 7

Then cover the blue letters with the red marker.

Two hands and a piece of paper are shown on a light wood-grain table. The paper is filled with numerous red scribbles and swirls, each with a small blue mark near its center. The right hand holds a white marker with a pink cap and appears to be adding more red scribbles to the paper. The left hand rests on the bottom left corner of the paper. The image likely depicts a game, a creative activity, or a learning exercise involving visual tracking or pattern recognition. A blue A and a blue k are written in the top left corner.

Step 8

Now take your completed colour filter and hold it over the covered letters. Something magical happens - the hidden letters reappear under the filter!

Two hands, a piece of paper, and a cardboard magnifying glass are displayed on a light wood-grain table. The paper is covered in red scribbles with small blue marks at their centers. The right hand holds the cardboard magnifying glass, which has a red-colored square window, over the paper. The left hand is positioned at the bottom left corner of the paper. The setup suggests a visual searching or decoding game using a homemade color filter.

The Science Behind It:

The colour filter works by filtering out red light, reducing interference from the red background, making other coloured text appear more vivid and clear. This makes it easier to see what's beneath the red covering.

Think about it - how would you make colour filters in different colours?

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