Gul Rukh and the Science of Chromatography

Gul Rukh and the Science of Chromatography

‘Are we there yet ma? I can’t wait to meet Lajwanti’, said an eager Sunita as the bus came to a halt. She hoped this would be the final stop as she was really looking forward to seeing her cousin after a whole year. ‘Yes we’ve reached finally. Please grab your bag and stay by my side,’ said Sunita’s mother while draping her dupatta around her head and stepping off the bus gingerly.

This was Sunita’s first visit to Karachi. Though her cousins from the metropolis often visited their home in Tando Jam, twelve-year old Sunita had never travelled outside her small town before. But this wasn’t merely a holiday trip as Sunita’s family was moving permanently to the city of lights where her father had found work in a local plastic-bottle manufacturing factory.

The family were glad that the bumpy bus journey was over. Jostled by the crowds, they somehow managed to make their way to the station’s exit. Sunita held on to her brother’s arm tightly and looked around for Lajwanti. She spotted her standing next to a fruit vendor, waving at them frantically. Soon Lajwanti and her father were welcoming the Dhillon family with beaming smiles and hearty handshakes. ‘I’m so glad you’re here Sunita,’ said an excited Lajwanti. ‘You will love being here and I can’t wait for you to meet all my friends.’ Sunita smiled back, equally excited about the prospect of spending time with her favorite cousin and of life in the big city.

Sunita’s first week in Karachi went by really quickly. Her uncle took her and Lajwanti to Saddar bazar where he said one could find anything and everything. Their families had a lovely picnic in the gardens around Frere Hall. And the week ended with a long day at the Clifton beach where the children enjoyed camel rides as the adults munched spicy ‘paapars’ and kept watch.

After a fun-filled week, It was time for Sunita to start at her new school. She was glad that she would be going to the same school as Lajwanti, even though her cousin was a year ahead of her. On the first day, she stood outside her house waiting for her cousin so that they’d walk to school together. At school, Lajwanti introduced Sunita to her friends and showed her around the campus. She made sure to check on Sunita during lunch breaks as well to help her adjust with her new surroundings.

Much to her dismay, Lajwanti noticed that as the days went by her little cousin gradually lost her usual chirpiness. She found Sunita unusually quiet during their morning walks to school and often found her wandering aimlessly around the campus during lunch breaks.

One day Lajwanti asked her cousin if anything was bothering her to which Sunita replied, ‘I want friends,’ she said, her lips quivering. ‘I wish you could stay with me all day Lajjo or that I had other friends. No one wants to be my friend.’

Lajwanti’s heart went out to her young cousin, she hugged her tightly, ‘You will make friends eventually Sunita. It wasn’t easy for me when my family first moved to this neighbourhood a few years ago and I started at this school. It took some time and now I have amazing friends.’

‘No I’ll never be able to make friends here!’ replied a teary-eyed Sunita. ‘You don’t know the whole story. A group of boys from my class have been bullying anyone who tries to befriend me. So nobody dares to speak to me or sit with me once the teacher has left. And yesterday something terrible happened as I walked back home from school.’

‘What happened?’ Asked Lajwanti worriedly.

‘As I came close to home, a group of boys wearing masks appeared out of nowhere and started throwing these paper balls at me,’ said Sunita rummaging in her bag to pull out a bundle of creased sheets of paper. She handed them to Lajwanti, who looked through them in shock. The pages were filled with cruel insults like ‘Go back where you came from,’ and ‘You don’t belong with us.’

‘Even though I didn’t see their faces, I’m sure these boys were from my class,’ continued Sunita. ‘I feel so scared of walking home by myself now. I really wish that my classes didn’t end earlier than yours, so that we could walk home together.’

‘This is outrageous! We must report this to headmistress Firdaus,’ retorted Lajwanti. ‘But first we need solid proof and I know exactly who can help us get it. Let’s go, It’s time we paid my dear friend Gul Rukh a visit!’ Concluded a determined Lajwanti.

‘It’s six o’clock, hopefully Gul Rukh would have some time for us if we hurry,’ said Lajwanti as she hurried on.

Sunita followed her cousin with a perplexed look on her face. ‘Who is this Gul Rukh? I haven’t seen her with you in school, have I?’

‘No she doesn’t go to any school. She works for the Maliks but she is awfully clever at solving mysteries. And she is amazingly great at science! You won’t believe all the magical things she does with everyday objects. Only it’s not magic it’s science, says Gul Rukh.’ said Lajwanti. ‘I’m sure she’s the only one who can help us get us proof against these boys. We must teach them a lesson Sunita!’

Gul Rukh was done with her daily chores and was happy to see the two girls. ‘It’s so good to see you Lajwanti, I haven’t seen you in ages. What have you been up to?’ Lajwanti introduced her cousin to Gul Rukh and took no time to narrate their grievances to Gul.

‘You must help us get back to these boys, Gul,’ said Lajwanti. ‘Is there a way to prove that these letters were indeed written by Sunita’s class fellows? There are seven boys in her how can we ascertain which ones were involved? Remember Sunita couldn’t see their faces as they were wearing masks.’

‘Here’s what we could do,’ replied Gul Rukh. ‘This will involve a bit of risk but we can prove that these notes were indeed penned by our suspects. They might have disguised their writing but we can analyse the ink to find out which pen was used to write these notes.’

‘How on earth will we do that?’ Asked an astonished Sunita.

‘Well we will need samples of ink from each of the boys pens. Then we will use a scientific technique called chromatography to find out if the ink from these notes matches the ink from any of our suspects’ pens’ explained Gul. ‘You’ll have to be brave Sunita and get me samples of inks from their pens. Do you think you’ll be able to do that?’

‘Of course we can! I’ll help you collect the samples during lunch break tomorrow’ replied Lajwanti while a nervous Sunita nodded silently.

‘Great I’ll keep everything ready. I’ll see you both at six tomorrow.’ Beamed Gul.

Sunita found it very hard to concentrate during lessons the next day. She felt both excited and a bit terrified. She was glad she wasn’t doing this on her own.

‘Come on quick let’s do this before anyone sees us’ whispered Lajwanti to Sunita as the girls slipped in to Sunita’s classroom quietly. Everyone was in the playground and the girls had only fifteen minutes to get their samples before they all came in for lunch.

gul-rukh-chromatography-1 gul-rukh-chromatography-2 gul-rukh-chromatography-3
Lajwanti fished out four glass bottles neatly labelled with the names of their suspects from her pocket. She quickly handed three of them to Sunita. The girls then collected a few drops of black ink from each suspects’ pen, making sure to not take too much to avoid raising suspicion.

With the samples safely in Sunita’s bag, the girls made their way to Gul Rukh’s house after school. They couldn’t wait to find out more about chromatography and how it was done.

Gul Rukh led them into the basement where she slept and did all the cool science experiments in her free time. She often used these experiments to help out her friends in distress or simply to have fun.

She showed them how she had carefully cut out the letter ‘O’ from one of the rude notes. ‘We will now draw matching Os using ink from each of the four samples you’ve collected my friends,’ explained Gul. She carefully dipped a Q-tip, using a new one each time to draw four Os on a piece of filter paper.

‘What will happen to these Os Gul? How can we tell which of these four inks was used to write these horrible notes?’ Asked a curious Lajwanti.

‘Well very few things consist of a single substance as most things are mixtures of different substances. For example, a perfume may contain dozens of different substances, each one of which can influence the overall smell of it.’ Replied Gul.

‘Chromatography is a method of separating out materials from a mixture and it is used for all sorts of purposes, e.g. for checking that our food and our medicines don’t contain dangerous impurities. Also police forensic scientists often use chromatography to identify substances found at crime scenes.’ Continued Gul.

‘Ooh I’d love to be a forensic scientist when I grow up’ remarked Sunita. ‘How will chromatography help us? All these samples of black ink look the same to me.’

‘They might all just look black but black ink is actually made up of different colours. These different colours are different substances. We will now peg this piece of paper containing an O from the note along with the Os we have drawn on filter paper using ink samples from our suspects above a tray of water. We’ll make sure that the bottom edges of the filter papers are just touching the water.’ Explained Gul Rukh as she lowered both the filter paper and the piece of note into water. ‘Now we just have to wait and watch.’

‘Oh and you can see that I’ve labelled each O with the first alphabet from the suspect’s name so that we would know who the ink belonged to,’ added Gul Rukh.

The girls watched as the water moved up the paper. ‘As the water moves up, it mixes with the ink samples and the ink dissolves in water. Together the mixture moves up the paper. But as I said before, black ink is a mixture of different colors. And in a bit you will see how all these different colors will separate out from our samples of black ink,’ continued Gul.

‘But the exciting thing is that some of these colors in the ink will stick strongly to the paper and hence not dissolve very well in water. These colors will not move up the paper very quickly. Other colors don’t stick to the paper very well and are carried along quickly by the water. These move furthest up the strip of paper. You can imagine a competition going on between the paper and the water for the different colours.’

‘But what if the note had been written using a permanent marker? Ink from a permanent marker doesn’t dissolve in water, how would we have separated the ink then?’ Asked Lajwanti.

‘That’s a good question Lajjo.Certain colors, like permanent ink will not move at all because they do not dissolve in water. If we want to get them to move we would have to use a liquid that the color does dissolve in, like alcohol,’ replied Gul Rukh. ‘There’s alcohol in nail polish removers you know, so we could have used that instead of water if these notes were written by permanent markers.’

Lajwanti and Sunita looked impressed, they thought Gul Rukh was amazingly clever and cool to know all this and that too even without going to school.

After a few minutes the girls dried the papers off and compared the ink patterns. It was easy to see which ink pen had been used to write the note. They now had their proof. The ink on the note matched with the ink sample labelled P which had come from Pervaiz’s pen.

The next day, Lajwanti stormed into Sunita’s classroom just as the bell for lunch break went off. Sunita watched nervously as her cousin strode up to Pervaiz, the tallest and scariest boy in her class. She held out the notes and looked at him questioningly. ‘Can you explain these?’ Asked a livid Lajwanti.’And before you deny writing these let me tell you that we can prove using chromatography that these were indeed penned by you,’ she added.

‘Using what? What is chromatography?’ Asked a puzzled Pervaiz.

‘Never mind that, I will report you to headmistress Firdaus if you don’t own up to these and apologize to my cousin Sunita. You and your group of friends must stop harassing her. Stop being mean to her because she’s different than you. She comes from a different faith than you but she has feelings just like you. You wrote insulting things about her and her faith on these notes and you’ve made her life hell by not allowing anyone to befriend her. You must stop and let her be. You’re not being cool, you’re being cruel!’ Said Lajwanti with hurt in her voice and tears in her eyes.

Pervaiz couldn’t bear to look into her eyes. Nobody had confronted him in this manner before. All the boys around him, particularly his elder brother Nasir had always told him that bullying and laughing at others would make people fear and respect him. But right now all he felt was humiliation. He looked at Sunita, cowering behind her desk and felt even more humiliated at his behaviour. He walked up to her and murmured an apology before quickly exiting the classroom.

Sunita looked at her cousin who seemed equally astonished at the fact that they’d managed to get the message of love and peace across to one of the scariest bullies in their school. They just couldn’t believe it!

Gul Rukh and Her Science Adventures

Gul Rukh and Her Science Adventures

Twelve-year old Gul Rukh woke up by the sound of shuffling feet around her and the morning lights piercing in through the windows. Around her, the Malik household was waking up to a perfect Sunday morning. Gul Rukh was in for a long day though as the Maliks were hosting a big ‘dawat’ tonight and she would be helping Mrs. Malik make all the preparation for it. Her spirits dampened as she imagined a long day in the kitchen, scrubbing huge piles of dirty dishes and ladling endless cups of tea for the guests.

A sharp sound emerging from the mobile in her pocket suddenly made the morning seem a bit cheerful. She glanced anxiously at the adults around her to see if they had noticed the sound but they seemed oblivious to it. She rushed to the bathroom and fished out an ancient-looking Nokia from her pocket – it was a parting away gift from her science teacher Miss Ayesha. Gul had left her village, school and friends to come work for the Maliks in the megacity Karachi. ‘Good Morning Gul, I hope we can chat for a while before you start your day’ read Miss Ayesha’s message.

Gul started typing a reply slowly as using a mobile phone was still a novelty for her. The phone had helped ease the terrible ache she felt for her school friends back home and their shared joy for Miss Ayesha’s science lessons. Miss Ayesha’s recent addition to the local girl’s school in their village had injected a great deal of joy into the girls’ otherwise dull school life. Each morning they waited eagerly for her to pull out props from her canvas tote bag. She used these to kick off her lessons with either a fun experiment or a captivating story featuring exciting elements from the world science. Being miles away from home, Gul was glad she had a way to stay in touch with her favorite teacher and school friends.

‘I’m up and have lots to do today but I get so happy when I receive messages from you during the day’ replied Gul. ‘I hope the mobile hasn’t landed you in any trouble Gul’, responded a worried Miss Ayesha. ‘No it works like magic, none of the adults can hear my phone ringing or receiving messages. It’s my secret friend here’, replied a chirpy Gul Rukh. ‘I’m so happy to hear that, but remember this will not happen around everyone. Just be careful while using your mobile around people under the age of twenty’, wrote Miss Ayesha. ‘Yes I’m always careful around the Malik children, Shahzwar and Sarah as they are my age. But I have to run now. I can hear Mrs. Malik calling out for me. I look forward to reading your messages during the day Miss Ayesha.’ Gul typed in before stuffing her secret friend deep into her pocket and hurrying off to the kitchen.

Questions for readers:

Is Gul Rukh’s mobile really magical? Why can’t the adults hear the sounds from her mobile?

To understand how the special ringtone in Gul’s mobile works we need to understand how sound is produced and what sound frequency is. Sound is the energy things produce when they vibrate (move back and forth quickly). If you bang a drum, you make the drum’s tight skin vibrate at very high speed (it’s so fast that you can’t usually see it). When the skin moves up, the air is squashed together (compressed) and the air pressure becomes higher than normal. When the drum’s skin moves down, the air expands and the air pressure becomes lower than normal. These pressure differences in the air travel away from the surface of the drum, like ripples in a pond.

So if something is making a sound, some part of it is always vibrating, even though you might not always see the vibrations. Vibrations cause molecules around them to compress and stretch alternatively producing sound waves. How frequently a wave oscillates between these two states is called its frequency and it’s measured in Hertz. The faster the sound wave oscillates, the higher pitch it has. High-pitched (high frequency) sound waves can be pictured as being squashed closer together with fewer gaps between the waves. However, low-pitched sounds have wider gaps between waves.

According to Gul Rukh, the adults can’t hear the sounds coming from her mobile. How is that possible, aren’t all humans capable of hear all the sounds produced around them?

Well we humans may think of the world as a noisy place but we can in fact only hear a small proportion of the sounds around us. Many of the sounds that animals emit are outside the range of our hearing. In the same way not all animals are able to hear all the sounds that humans can. Consider dog whistles, which canines can hear but we can’t. That’s because dogs’ ears have evolved to detect such high-frequency sounds. Similarly, it has recently been discovered that elephants communicate over long distances using super-low- frequency sound that we’re also unable to hear. The human hearing range is between, 20 to 20 000 Hertz. To give you an idea, the speaking voice of a woman is generally between 165 to 255 Hertz.

But why is it that only adults couldn’t hear the ringtone on Gul’s mobile? And why did Miss Ayesha warm her to be careful while using the mobile around people younger than twenty?

There are thousands of hair-like cells found inside your ears that are responsible for picking up sounds of different frequencies and sending signals to the brain where they can be processed. As you age, the continual exposure to noise and loud sounds damages these cells and it becomes impossible for you to hear certain high frequency sounds, which you could hear when you were younger. So unlike other body cells, your ear cells won’t last forever and as you grow older higher sound frequencies will start falling out of your hearing range.

This process is called presbycusis, the onset of which is sometimes observable in people as young as eighteen. Presbycusis happens as our ears age naturally, so it’s nothing to be alarmed by.

Do try this at home:

Would you like to test out how old your ears are? Or maybe download your own secret ringtone, which adults can’t hear?

You can test out sounds of different frequencies on our website to find out how old your ears are. You can also test these on your friends, grandparents, younger and older siblings or even your dog to find out which sound frequencies they can hear. Visit our website to think and work like real scientists as you perform this exciting experiment. And while you’re at it why not download a secret ringtone, which can’t be heard by adults above a certain age. If you don’t believe us, check it out for yourself at: