This day has been carefully marked in Omar’s calendar; it is his first day in swimming training after a long year of hard studying. This training is the gift that his father promised him for doing well throughout the year, and he has been over the Moon.
As they arrive, Omar grabs his bag and goes into the club so excited. He changes his clothes, put on his swimming suit, brings his board, and heads towards the pool. The captain tells the group to warm up.
Omar starts to do so, but not fully concentrated on the exercise; the sparkling water under the sun has captured his attention, especially the pool bottom, which he thinks would be his savior as he is still new to swimming. In every turn and as he comes closer to it, he tries to figure out how deep it is, not in numbers, but in his own calculations. According to that, he has weaved all possibilities.
As the captain asks them to get into the water with their boards and start kicking with their feet, Omar’s heart starts to skip a beat. He does what the captain says, but as he jumps into the water, he feels he has gone deeper than he thought and the bottom is not that near as he supposed!
He starts to cling hard to the swimming board, refusing any possibility of letting it go. While his body is busy following the captain’s instructions, his mind has been captured by other thoughts, “Why does not the bottom appear as it is? How could it be so deep while I can see it close? Why does this happen in water? On land, you see exactly where your feet tread, with no manipulation”.
Omar keeps these questions inside his head till he gets back home and searches the internet for satisfying answers.
****
As the training ends, he heads towards his father, who has been watching him closely during the whole training. He asks Omar about the training and Omar replies in almost a whisper, “Good. It was good”.
Omar looks to his side and finds a glass of lemonade; he stares at it as the straw looks bent. He takes it out of the glass, but finds it ok. As he puts it once again into the glass, it looks bent under the surface.
He asks his father, “What is wrong with this straw? Why does it seem broken while inside the glass and ok when it is outside?” His father replies, “Yes dear, this is what happens because of refraction”. “Refraction?” Omar repeats, “What does it mean? And why does it happen, Dad?”
“Well, it happens when light passes from one medium to another; for example, when it travels from water to air or vice versa. As light travels in different speeds through these mediums, this causes changes in direction”, says the father.
Omar asks, “What is the result of that?” “It causes light to bend, as you can see through the glass. The straw looks bent under the surface, as you can also see the part of the straw under the surface is bigger than the outer part”, the father adds.
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“This also goes for the pool bottom?” Omar asks with curiosity; “Yes, exactly,” the father replies. Omar looks so excited to figure out the dilemma in his head so fast. His father adds, “The apparent depth in which you see the bottom is not the real one; it is much closer”.
Omar says in agitation, “Yes, yes, I have noticed that”. His father adds, “Refraction is evident in other things as well; the rainbow, for example, and you know, it works perfectly with something that we use daily without too much thinking”, Omar keeps thinking.
The father says, “This law also explains how we see things and how our eyes work; without refraction, we would not be able to focus light onto our retina*, and this would affect how well we see,” and adds, “It is also applied in magnifying glasses, to maximize the size of things or bodies, and optical lenses, which are used to see better”.
“Wonderful,” Omar replies, “I could have never expected to know something that has too many applications. Thank you, daddy”.
****
With this new precious piece of information, Omar has felt more nourished and curious to read more on this law of refraction as his mother has always told him “It is better to apply knowledge into practice to fully understand it”.
On their way home, Omar’s father stops by an electronic shop to get something and gets out of the car. While waiting for him, Omar looks out of the car window to the other side of the street and sees an aquarium and a fish store. He stares at the beautiful colorful fishes swimming with no fear of how deep the bottom is and he thinks, “You, big fish, I know you are not how you seem”.
Glossary
*Retina: A thin layer of tissue that lines the back of the eye. Its purpose is to receive light that the lens has focused, convert the light into neural signals, and then send these signals on to the brain for visual recognition.
References
coolscienceexperimentshq.com
healthline.com
sciencelearn.org.nz