On Independence Day this year, Hanuman and Kiran found Prof Tung Tang playing something made out of a leaf, and they found all about the science of sound
August 15. It was the Indian Independence Day. Hanuman and Kiran got up late to the tune of patriotic songs ringing in the air all around.
The prancing little boy and his sister looked around for the caps and the flags that they had been given from school the previous day—their pride adornment for the day.
“Take the jalebis that I have fried in the morning for Professor,” their mother said as soon as she saw they had got up and were making arrangements to go Professor Tung Tang’s house.
Ah! That was the wonderful smell that was making them hungry.
Brother and sister quickly freshened up, and with the packet of jalebis in hand, hopped across the street, munching at the delicacies, soaking all the lovely songs they are used hear twice a year – August 15 and January 26.
Entering through the garden, they found the door ajar, and was a bit surprised to find no one in the living room. They heard a strange sound from upstairs and rushed up.
The professor had put together all his musical instruments that had so far been lying all around the house in his store room and was sitting on the floor playing a strange leaf.
Hanuman went to him and curiously bent over to take a closer look. The edge of a leaf was curled into a semi-circle and Professor had placed the arch between his lips and was blowing across it.
“What is this?” he asked, his eyebrows furrowed, as Professor passed on the leaf to him. Kiran, who had lined up behind him, curiously looked on and handed over the packet of jalebis her mother had packed for the Professor.
“It is a leaf instrument, traditionally played by the Chinese,” the Professor said while opening the sweets’ packet.
“So how does it make this strange sound?” Kiran asked wide eyed. She had clearly not seen such a strange thing earlier.
“The leaf vibrates and so does the air trapped in the semi-circular curve of the leaf, as the player blows across the arch. Just like any other music –sound is produced when something vibrates.
“In case of guitar, violin, piano they are the strings.In case of drums they are the membranes and in case of flute and harmonium it is the air. Those vibrations are brought to the ear as sound waves,”
The Professor explained while picking up the different instruments from his collection to demonstrate the effects to the children.
Holding out a guitar to Kiran he said: “You could play a string and see how the wooden base vibrates, increasing the sound many times”.
“But how does this reach the ear?” Hanuman interjected.
“When an object vibrates, it causes movement of air particles. As they particles vibrate, they cause more particles to vibrate which in turn reaches any ear which is within the range of their reach,”
Professor explained handing over the guitar and lightly beating on a drum.
“But Professor, I have seen you putting parts together to form new kinds of instruments and always wondered what you do,” Kiran said, inspecting the guitar closely.
“Oh, all I do is combine different kinds of vibrations together to try and create new kinds of music. Sometimes it is successful and created music, while in others it creates only noise,” Professor smiled.
“ Yes, yes I know… I have heard that AR Rahman also combines different instruments to create his musical magic. But what is the difference?” Hanuman interrupted him while trying to play one of the instruments.
“Regular and softer sound is usually pleasant to us and hence called music, while irregular sound,particularly the louder ones,is called noise,” Professor said trying to demonstrate it on the drum.
“Twang,” Hanuman’s efforts had produced a loud discordant note on one of Professor’s prized instruments and all of them started.
“What makes it so loud Professor? Is this one of these instruments of yours that creates ‘noise?” Hanuman was looking at Professor from the corner of his eye, displeased at his owned failed efforts.
“No dear, there is a certain way of playing it. Otherwise it vibrates too fast and produces loud sound that this unpleasant to the ear.
“It hits the eardrum too hard and this is uncomfortable for the membrane in the ear,” Professor said playing some soft notes on the same instrument as Hanuman handed it over.
“And why is music pleasant and irregular sound unpleasant professor?” Kiran looked at Professor inquisitively.
“Oh, that’s because our nerve cells like rhythmic, soft sound and dislike irregular loud sound that hurts it.”
The three of them were now concentrating on the remaining jalebis while trying out the different musical instruments Professor had put together over the years, making their own interpretations of noise and music in a new light of understanding.
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Archita specialises in science communication, and in this series she has created for children, she uses three fictional characters, Hanuman, a bit of an imp, his elder sister Kiran and Professor Tung Tang, a scientist who meddles in musical instruments.