Smell is probably the most common basic means of animal communication. Even the most primitive animals react to odours given off by their own, or 
other species.Animals may use scents, to mark out territorial boundaries, to attract mates, to warn off intruders and predators or, in some cases, to attract prey. Animals of all kinds rely to a great extent on their hearing ability in order to succeed and survive, and this is called acoustic communication. Among mammals, generally speaking, small animals squeak, and large ones rumble. The acoustic communication signal most frequently heard by humans is, of course, bird song. The largest of all animals, the whales, appear to be experts in the art of communication by sound, with each whale of the same species having its own favourite ‘songs’ which it repeats at intervals.Visual signals may take the form of gestures and displays, facial grimaces, body posture or mimicry. Each species has its own way of using its facial expressions, body language, gestures and body markings to communicate effectively.At another level, animals may communicate a simple message through the art of mimicry. The markings on the wings of the peacock butterfly look like large eyes to frighten off its enemies. The same is true of the harmless hoverfly that resembles the wasp.
Image is produced in a plane mirror by reflection. It is a virtual image, that is, it can only be seen in the mirror but cannot be projected on a screen like an image produced by a concave mirror or a lens. Every point on the virtual image corresponds to a point on the object in front of the mirror, but since the object and the image face each other we get the illusion of lateral inversion that is, the right side of the object appears to become left in the image. For the same reason, written or printed alphabets appear reverse when seen reflected in a mirror, except a few symmetrical alphabets such as M, O, W, T and Y.
gestures, body language, displays, and even markings on the A peacock’s extravagant display of feathers is a form of visual communication. The male rabbit will use the white underside of its tail to attract the attention of a female, while the female may use the white of her tail as a visual signal for her young to follow when she is leading them to the safety of the burrow.Dogs and wolves make use of body language, as do cats, monkeys and many other animals. The attitude of the tail when two wolves meet will indicate which of the two the superior is. Horses will hold their ears or tail in certain positions to signal pleasure or alarm. 
and sing cats when they meow and purr, and dolphins when they click and whistle. Many of these noises translate to simple phrases like ‘I’m hungry’, ‘I’m angry’, ‘feed me’ and ‘leave me alone’.Other animals use signals and sign language to talk to each other. Bees do a complicated dance to tell other bees in which direction to go to find food. Howler monkeys will howl to tell other monkeys to keep off their territory, and some birds sing both to attract mates and defend their Will we ever be able to understand what animals are saying? Maybe, one day. It’s possible that, in the future, we’ll have computers so powerful that they’ll be able to decode the dolphin clicks even to translate Cuttlefish into English! 
though, when they are hurt, they purr to comfort themselves.
Burning is a chemical process in which the material which burns combines with oxygen with the generation of large amounts of heat. As a result the temperature of the burning material rises to several hundred degrees Celsius and it may burst into flames. Therefore, any substance that readily combines with oxygen at a few hundred degrees and produces a lot of heat will burn if ignited. Such substances such as paper, wood, cloth, plastics, rubber, etc. are usually rich in carbon and hydrogen. Some volatile liquids such as alcohol, ether, petrol, etc. catch fire easily because they produce highly combustible vapours.
Foam or lather is nothing but a large collection of small soap bubbles. A soap bubble is, in turn, a very thin film of soap solution enclosing some in air. Because of the low surface tension of soap solution, the film can stretch and spread and form innumerable bubbles with a very large total surface area. Because of this, whatever slight tint present in the thin film of the coloured soap solution gets subdued. Although a soap film is more or less transparent, the lather or foam looks white because the light striking this large collection of bubbles gets scattered. That is why all kinds of foam look white.
As our body is not a flat surface, whenever any part of the body is hit by a stick or rod it makes contact with only a small part of the skin depending on the diameter of the stick or rod. When hit with a thin cane, it hurts a lot because the flexible cane has a smaller diameter and contacts a thin strip of the skin on the body b wrapping around the surface. Since the force experienced per unit area is large, the cells under the area of contact are crushed causing either a swelling or bruise in that part of the body. On the other hand, a thick stick has a larger diameter and does not flex easily. When it hits the body the total area of contact is smaller and as the contact point is much flatter the force gets distributed over a large surface area thereby causing less pain.
Spectacles are made up of lenses and are used to improve vision. For nearsightedness, concave lenses are used and for farsightedness convex lenses are used to give clear images. A microscope is an instrument which gives enlarged view of small objects. In an optical microscope, the objective makes a real image of the object which is further magnified by the eyepiece for the eye to see a magnified virtual image. The distance at which the magnified virtual image is formed can be adjusted by moving the eyepiece to suit the power of the spectacles one uses. So, one need not use spectacles while using a microscope in order to see the magnified image clearly. Besides, wearing spectacles also draws the eye of the observer away from the eyepiece thus reducing the field of view.
The pitch, loudness, duration and timbre are the four qualities which define the structure of a piece of music. The pitch or the high-low aspect of the sound is considered to be the most important unit in structuring music. The timbre or the ‘tone colour’ is the sum total of the simultaneous motions produced by any vibrating medium. This is unique for each instrument. The timbre also defines the fineness of the sound produced by an instrument. Differences in timbre of sound produced by different instruments are responsible for the different musical qualities of the various instruments. Thus musical notes produced by different instruments sound different inspite of the pitch being the same.[custom_search_and_filter]