"WIND: A GIFT or A WRATH"

PART-2

Vayu’s father then switched on the laptop and inserted his 3G dongle into the port. Within few seconds he was online on the skype. After a minute or so Skype showed an incoming call from a person called David. Vayu’s father connected the call and said, “Hello David, how are you? Long time dude.”

“Hi Rajiv. I am perfectly fine. Oye Balle balle!” David said while raising both his hands in air doing traditional bhangra movement.

“Ha ha! What is this David? Are you learning Punjabi?”

“Ha ha ha! No no brother. It’s just that recently some Punjabi family has shifted in our neighborhood. Whenever we meet them they always say Balle Balle. Hence, I also said so. I must tell you Rajiv there are so many Punjabis shifting here from India. Canada is becoming mini Punjab. You also plan and come stay with us. It would be lovely.”

“Yeah! Sure David some day we will definitely come. Oh! I completely forgot. David this is my son Vayu and his friend Sarthak. Kids say hello to Uncle.”

“Uncle??? Rajiv do you think I am so old? I will not leave you. No need to call me Uncle, kids. Anyways how are you doing?”

“Hello sir. We are fine. It is nice to meet you.” Both Vayu and Sarthak said.

“Why are you both sounding dull? You should be more energetic. I will tell you a nice joke which will make you laugh.” David said.

“Wait David…. Do you remember Harshit, who had shifted to Australia last year?”

“The same lean guy with a moustache. How can I forget him? I have thrown ketchup on his shirt during our college days. Ha ha ha!”

“Yes yes that Harshit only. He is also calling me on Skype. Wait I will bring all three of us on conference.”

“Hello Harshit. How are you? What a pleasant surprise.” Vayu’s father said.

“Hey ya Rajiv. Hows ya? I am fine. Yeah! Dude, it has been a long time. Today I was a bit free so thought to call ya. What are ya doing?” Harshit said.

“Nothing much Harshit. Its good you called. You remember David who went to Canada, he is also on Skype. Wait I will add you in conference.”

Vayu’s father added him to the ongoing call.

“Hello Harshit bro how are you?” David said.

“I am fine dude. Hows ya? How’s the weather in Canada?”

 “It’s very cold here dude. Constantly snow is falling. You tell what about Australia?”

“Dude its very hot here. Send some cool air to Australia also. We are always sending wind to others but do not receive any.”

“Ha ha ha! Dude we ourself receive winds from countries like India. How can we send it to you?”

Both Vayu and Sarthak started laughing. They thought that David was kidding.

“You did not introduce me to these kids Rajiv.” Harshit asked.

“Oh! I am sorry. Harshit this is my son Vayu and he is his friend Sarthak.”

“Hello Kids. How are you and why did you laugh?”

“Hi Sir. We are fine. We laughed on the joke told by David sir about wind.” Both of them said.

“But kids, David is right they do receive winds. You don’t know this?” Harshit asked.

“No Uncle. Is it really true?” Vayu said and looked towards his father.

“Rajiv I am surprised to know that being a son of a great scientist they do not know the concept of Global Winds. Have you never told them?”

“No Harshit not till now.” Rajiv said.

“Ok. Doesn’t matter today we will explain them what are global winds and how are they distributed around the world. What say Harshit?” David said excitingly.

“Yeah dude sure why not.”

“It would be very nice friends.” Rajiv said.

“But let me first explain them about Coriolis force. It will take just 5 minutes. Stay on line. You both could also see and correct me where ever I am wrong.” Rajiv continued.

“Yeah! We will love to see your explanation. You always try to explain in different way.” Harshit said.

“Vayu go and bring football from the boot of our car. Meanwhile we will go to that merry-go-round.” Rajiv said pointing towards the Red and blue coloured Merry –go-round.

Vayu following his father’s order ran to the car to bring the ball. On the other hand Rajiv and Sarthak went to the Merry-Go-Round. Rajiv placed his laptop on a nearby bench with the camera facing the Merry-Go-Round so that both David and Harshit could also see. He then asked Sarthak to go and sit inside the Merry-Go-Round.

By now Vayu had also come carrying a football. He saw Sarthak sitting in Merry-Go-Round and asked his dad, “What is Sarthak doing there?”

“Wait Vayu you will get to know.” Rajiv said and took the ball from Vayu and gave it to Sarthak.

“Vayu go and stand a little far away. I will rotate this Merry –Go-Round.”

Vayu did as asked for. He moved few steps back from Marry-Go-Round.

“Now Sarthak I am going to rotate this Merry-Go-Round and when I say you have to throw this ball.”

“Ok Uncle.”

Rajiv rotated the Merry-Go-Round and when it came into motion, he told Sarthak to throw the ball. Sarthak threw the ball to the ground.

“Vayu what did you see? What path did the ball follow?”

“Dad the ball went in a straight line.”

“Nice. We will do this one more time.”

Rajiv did the same procedure again but this time he asked Sarthak, “Sarthak what did you see?”

“Uncle the ball took a curved path.” Sarthak said.

Vayu was surprised to hear his answer. He asked, “Dad how is it possible? I saw that ball fall in a straight line but Sarthak is saying he saw a curved path. Was I wrong?”

“No my child. You both are correct. What Sarthak saw was because of Coriolis force. Come let us join our Skype friends then I will explain you in detail.”

They returned to the bench and sat down, Rajiv keeping the laptop on his lap continued, “Children Coriolis force is a fictitious force i.e. a force which is actually an illusion. Moreover it only acts on a moving objects and only when you are taking measurements from rotating prospective. The same happen on earth. When on earth wind flows in certain direction the rotation of the earth on its axis causes the Coriolis effect on the wind and as a result wind deviates from the straight path and follows a curved path. Hence, when the rotation of the Earth causes the moving air and water to change directions it is known as Coriolis Effect. In the Northern Hemisphere of the Earth Coriolis force causes the winds to curve to their RIGHT and in the Southern Hemisphere it causes the winds to curve to their LEFT. I hope now you have got a basic idea of the Coriolis force.”

“Yes yes. We have.” Both the kids said.

“I must say that was a wonderful and the easiest explanation for coriolis force Rajiv.” David said.

“Thank you David for the appreciation.” Rajiv said smilingly.

“C’mon guys don’t forget the task. We have to explain them Global Winds not just Coriolis force. Let us do that. I have to go somewhere after half an hour.” Harshit said.

“Oh! Yes yes. David will you start or shall I?” Rajiv said.

 “I will start Rajiv.” David said excitingly. “Kids first of all you should know that there are 3 types of winds that we experience on Earth. One is Permanent or Global Winds that I and Harshit will explain and the other two are Seasonal and Local winds that Rajiv can explain you afterwards. Right Rajiv?”

“Aye aye Captain!” Rajiv said and all started laughing. Vayu and Sarthak were very excited as they were going to learn something new and interesting.

“Ok ok no jokes for next half an hour. Let us begin.” David said and shared a photo of Earth’s Globe on Skype so that all of them could see. “Ok kids, first tell me do you know how the hot air and cold air flows?”

“Yes Uncle. Dad had told us today only. Hot air being lighter rises up and cold air being heavier sinks down.” Vayu said.

“Very Good Vayu. And this concept is known as Convection. In simple terms Convection is the circular motion that happens when a warmer air or water which is less dense rises up and colder air or water which is denser sinks down consequently resulting in transfer of heat.” David explained.

“Ok now can you see this Globe picture I have shared here?”

“Yes Uncle.” Both said together.

“So can any of you tell me that in which part of the Earth receives maximum rays of the Sun and which part receives the minimum rays from the sun?”

“It’s easy Uncle. The equator will receive the maximum rays and the poles, both north and south, will receive minimum rays from the sun.” Sarthak said.

“Brilliant. I must say you both kids are very intelligent.”

“Thank you Uncle.” Both of them said blushingly.

“You are correct Sarthak. At the equator the sun rays directly hit making an angle almost equal to 90 degrees and at the poles the sun rays hit at a very small angle. That is the reason the Polar Regions are very cold and the equator is very warm.” David said.

Without waiting for anyone to say anything he continued, “I hope that you both know that our Earth rotates on its axis.”

“Yes Uncle we very well know that.” Both said in unison.

“So let us assume for some time that the Earth is still. God has stopped Earth’s rotation for some repair work.” David said and started laughing. With him every one else also laughed.

“No jokes David.” Harshit said with a wink.

“Oh! Yes. Sorry sorry. Now as we know that the Sun rays hit directly at the equator hence, the air present there is very warm. And at the poles the air is very cold. According to the concept of Convection we just learned that the warm air from the Equator rises up in the atmosphere to some level from where it will start moving towards the poles, both north and south, and the cold air from the poles sinks down and moves towards the Equator to form a Convection Loop or a Convection Cell. This happens at all areas of the Earth.” David said and showed them a picture depicting the movement of air.

“But actually this is not the case.” Harshit said. “You take some rest David. I will explain further.”

“Sure Harshit. Go ahead.”