Blog

Why does not sound travel in vacuum but light does?

The basic difference between a sound wave and a light wave is that the former is a mechanical wave while light is an electromagnetic (EM) wave. Mechanical propagate by the actual displacement of physical particles. Each particle oscillates about its mean position in a synchronized manner to cause energy propagation in a mechanical wave pattern. In case of EM waves, electric and magnetic fields ‘oscillate’ about their mean zero in mutually perpendicular planes and cause wave motion. Mechanical waves require particles to oscillate and enable it to move on. Hence, they require some medium (to provide these particles) for travel. EM waves consist of only change in electric and magnetic fields. So, they do not need any medium for propagation.

Why is it possible to hear noises from far away clearly on cool damp evenings? Is it because sound travels better in cool, damp air than in dry air?

The most likely explanation for this phenomenon is that warm, damp air at ground level was sitting below a layer of drier, hotter air above. This results in refraction of the sound back down towards the ground and also the unusually high propagation distances – you hear sound which, under normal circumstances would pass over your head.

Also another explanation could be that sound travel better at night, but the reduction of daytime noise means that continual sounds become more apparent. In the evening it is usual for the temperature near the ground to fall more quickly than that higher up, causing a temperature inversion. It is not uncommon for there to be a change in the air’s moisture content at the top of this inversion layer.

The change in temperature and moisture lead to a density discontinuity which refracts sound waves much as the refraction of light causes a mirage. Sounds are trapped near the ground rather than dispersed. The wind speed in this low-level inversion layer is also normally lighter and this adds to the effect.

Marvelous Mahouts

It requires a lot of skill for a puny man to control a mammoth elephant. Mahouts have learned the skill to make the elephants do his bidding by uttering a command or by a gentle prod with his hands or legs. A rained elephant will turn to the left, when the mahout prods him gently with the toe of his right leg. If the repeats this manoeuvre with his left leg, prodding it to turn right, then the elephant will turn right. If he uses both his big toes to prod the elephant forward, then it moves forward. If the bottom portion of his bare leg is pressed backwards, the elephant takes it as an instruction to move backwards.Mahouts use about 20 words to give commands; they are a mixture of English, Urdu and Malayalam. Lots of elephants are brought from Bihar; they prefer their mahouts to talk to them in the national language-Hindi

What is an alarm call?

 An alarm clock is something that helps you wake up in the mornings, but an alarm call by animals means something quite different! It is a sound made by animals when they sense danger and want to warn others of it. Birds have loud alarm calls that warn other birds that an enemy is near. Different species have different alarm calls, but the meaning of all calls is clear-WATCH OUT! DANGER!’

Which animal beats its feet?

When you think of frogs, the word ‘croak’ comes to mind. Well, the Malaysian Tree frog is a very smart frog. It knows that in the noisy rainforest of Malaysia, its croaks will not be heard above the calls, shrieks and hoots of other animals.So what does the female tree frog do when it wants to attract a male? She taps with her toes on the leaves of a tree. The vibration is too delicate for human’s man to feel or hear. The male frog though, can feel the taps. He knows that the female is trying to attract him. The male frog will come rushing towards her.  The beating of feet by the female tree frog is, therefore, an important form of communication that is necessary to ensure reproduction.

Why don’t animals talk like humans?

Wouldn’t it be lovely if your pet dog or cat could talk to you? Well, the fact is that though animals have voices, tongues, lips, teeth, and a nose like we do, they can only make noises and not talk. Even when a parrot repeats things that you say, it is not talking. It is just copying the sounds that you make.The reason may be that only humans have a larynx or voice box that is slung low, so that it can resonate to produce something more than a grunt or a meow. It may also be that our brains are more evolved… in any case; the ability to communicate through speech makes human beings different from animals                                                                                                  

                                                                                                                                                                                  

                                                                                                                                                                                

                                                                                                                                                                                   

What are the functions of animal communication?

We know that animals communicate. But why do they communicate? The first reason is to warn off other animals from their territory. Through their communication, they challenge rivals and establish their superiority. The courting ritual of animals is carried out through their communication. Some animals display body parts to show they are ready to mate or to attract the opposite sex. Others stand or walk in a particular way, while still others release particular scents. Many animals have characteristic mating calls that are unique to the species, thus allowing them to mate only with members of their own species.Animals also make “food calls” that attract a mate, their babies or their friends to a food source. Some signals are made to warn other members of their group of a threat. There are also some signals that are used to modify the meaning of signals that follow, or came earlier. In short, communication helps animals to co-ordinate the vital functions of their lives …mating, gathering food, hunting, caring for their young, marking their territory, and defending themselves

How do animals transmit messages?

Animals transmit messages animals and signal each Other in many ways. Facial expressions and body language convey a lot of meanings. The way an animal stands or holds its ears tells its rival or another animal in the group something about its intentions. Many animals also exchange visual signals.Similarly, animals convey messages through the sounds they make, and the scents they release. Animals often anoint their territories with scent marks that other animals can read as they pass by. So, animals are really very clever at transmitting messages without talking like we do!

What is Zoo semiotics?

Zoo semiotics is a very long word indeed, isn’t it? But it actually has quite a simple meaning. It means the study of the different ways in which animals communicate with each other.We all know that animals cannot talk, but this does not mean that they do not communicate with one another. They have several different ways of communicating, and this communication affects the behaviour of other animals around them. Zoo semiotics studies all this, and this science which is more than 40 years old, was founded by a distinguished American professor, called Thomas Sebeok