Science : Explore & Learn

gktalk_imran

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About this app

In science world app
1. Daily Life Science Queries
2. Interesting Science Facts
3. Science Quizzes
4. Option to put Questions in favourite Section

Example:
1.How are planes protected from lightning strikes?
Ans: A plane’s metal fuselage is effectively a Faraday Cage, safely conducting the current from where the lightning strikes to where it exits. But lightning can potentially induce secondary currents in cabling beneath the aircraft’s skin. So, for added protection, wiring and computers are electrically screened. The latest aircraft, like the Boeing 787 Dreamliner, are made of less conductive composite materials. Conductive fibres are woven into the skin to guide lightning safely around the plane’s body.

2. Why do people behave differently in a crowd?
Ans. They may wish to fit in by imitating others feel constrained by being observed, become excited by the noise and actions of the crowd, or may respond to local conditions and culture. An odd example is that in different countries pedestrians step right or left when meeting others on a crowded street. This is unrelated to which side of the road they drive on and appears to emerge spontaneously and then stick in each culture. Perhaps the most worrying behavior is when people feel less responsible for helping someone in trouble when there are others around. This ‘bystander effect’ is quite rare but more likely the larger the crowd.
3.Why do some people sweat more than others?
Ans. Receptors in the skin detect changes in the external temperature and pass this to the hypothalamus region of the brain, which can make the body sweat in response. An overweight person is better insulated and has a smaller surface area to volume ratio. Their core temperature will be higher for a given external temperature, simply because it’s harder for them to dump excess metabolic heat, and they will sweat more as a result. Fit people also sweat more than normal. This is because their bodies have become conditioned to start sweating sooner in response to exercise, for optimum cooling.

4. Why do humans show affection by kissing?
Ans. It’s not just humans that enjoy a smooch; lots of animals have courtship behaviours involving the mouth. Pigeons touch beaks, cats and dogs nuzzle each other, male fruit flies lick the females. At the most basic level, kissing is just a way of tasting and touching a potential mate, as part of the process of assessing suitability.
In primates though, kissing might also be a behaviour that has transferred from maternal feeding. We depend for our first meals on our ability to suckle, and the positive feedback mechanisms that evolved to encourage infants to do this last into adulthood. Kissing triggers lots of hormone changes, including raising oxytocin levels – the hormone that creates a sense of attachment.
Kissing is virtually universal in all human cultures, so it’s possible that it is instinctive.

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