1. Use the lid to trace a circle on the white paper and cardboard. Cut both of them.



2. Using a pencil and scale, divide the circular sheet of paper into 6 equal parts as shown, and colour each in a different colour: purple, blue, green, yellow, orange and red.



3. Glue the paper to the cardboard.




4. Make a small hole in the centre of the disc and poke a skewer through it. Hold the skewer and spin the colour disc.





As you spin the disc fast, you will see that the different colours start to merge and appear as one colour (white).


Think about


Why do the different colours combine and appear white?

First, the colours combine and appear as one because of the way our eyes read moving images. When the disc spins, our eyes cannot register the colours separately, and hence perceive them as one. Second, the colours combine and appear white because of the composition of white light. All types of light travel in waves of different frequencies. Our eyes can only see lights that travel within a specific range of frequency called the visible spectrum. This spectrum consists of lights of different colours: red, orange, yellow, green, blue, indigo, and violet. When these colours are combined or travel together, they fuse into one to form white light. So, when the disc spins, the colours combine and appear white.

Let’s Find Out

How are rainbows formed?


The (white) light that we receive from the sun is composed of several colours. When a beam of sunlight passes through rain drops (which is why we see rainbows mostly during the monsoon), at a certain angle on its way down, it splits into the different colours it is composed of, thus forming the rainbow.

Photo credit: Pixabay.com

Us and Them

Parrots are commonly known to imitate sounds such as the barking of a dog and security alarms. Sometimes, they also repeat words. Unlike humans, parrots do not have vocal chords or lips. Parrots use a vocal organ called syrinx that controls the movement of air within the throat to produce different sounds. The syrinx can also produce two sounds at the same time. The parrot’s thick tongue aids in speech. When air passes through the syrinx, the parrot moves its tongue to produce sounds.

tongue to produce sounds. Among all species of parrots, the African grey parrot is considered to be the most intelligent and has a greater memory. Hence, it is able to learn a greater vocabulary.

The African grey parrot does not only speak human language, but it is also the only bird known to understand what it speaks. It understands what each word stands for. Cosmo, an African grey parrot, would use different phrases depending on whether the owner was in the room or not. When the owner was away, it would use phrases that established location like “I’m here”, “Where are you?”. When the owner was in the room, it would use phrases to establish interaction like “Do you want to play?”

Alex, an African grey þarrot, was trained by researchers to speak 100 words, identify 50 objects, 7 colours and 6 shapes!