10 Important Science Questions And Their Scientific Reasons.

10 Important Science Questions And Their Scientific Reasons.

1. Why does a gun recoil when a shot is fired out?

Since the mass of the gun is much greater than that of the bullet; hence the speed of the gun is very small as compared to that of the bullet. Therefore, the gun moves backwards only by a small distance during recoil.

2. Why are passengers thrown in the forward direction when a running bus stops suddenly?

Passengers sitting or standing in a running bus share the motion of the bus. This means, the passengers in a running bus are also moving with the same speed in the same direction. When the running bus stops suddenly, the lower part of the passenger’s body come to rest, while the upper part continues to remain in motion. As a result, the passengers are thrown in the forward direction when a running bus stops suddenly.

3. An iron ball sinks, a ship does not, why?

In case of iron ball, its weight is more than the weight of water it displaces. In case of ships, the space inside being vacant, the weight of the ship is less than the weight of water it displaced. thus, whereas upward thrust is sufficient to balance the weight of the ship, it is inadequate to balance the weight of the ball.

4. Why is driving on a icy highway extremely dangerous?

For safe driving frictional force between the tyres and the road is an essential factor. When these frictional forces become less, the driving becomes difficult. As the force of friction between the tyre and ice is very small, therefore, driving on icy highway on icy highway becomes dangerous.

5. Why is a gap left at the joint between two rails?

A long railway track consists of many sections of steel called rails – joined to each other. While laying a railway line a small gap is left in between two rails at their joint to allow for the expansion during summer. If such a gap is not left at the joints of rails, the track will get deformed due to thermal expansion in summer, which may cause derailment of trains.

      Another method of allowing for the expansion of rails is to use a wedge joint between the two rails. When the temperature rises during summer, the rails expand and their ends side part each other.

6. Why does water get cooled in an earthen pot (surahi or matka)?

As earthen pot has small pores in its walls. When water is poured into it, some of it seeps through these pores to its outer surface. On reaching there, it evaporates. The heat required for evaporation is taken from the earthen pot and from the water in it. As a result, the water in an earthen pot gets cooled down.

7. Explain how bats use ultrasound to catch a prey.

Bats are usually active at night. They search out for their prey at night. They try to detect the ultrasonic waves emitted by them. The high pitched ultrasonic squeaks of the bat are reflected from the obstacle or the prey and returned to bat’s ear. The nature of reflection tells the bat about the location and size of the prey and they are able to easily attack them.

8. Why do diamonds shine at night?

The rays of light entering it get internally reflected from most of the faces, on account of high refractive index so, from a few faces that permit light to get out, a lot of light comes out.

9. Why does a straight stick look bent when partly immersed in water?

When the rays of light enter another medium, they change their path due to refraction, so the stick looks bent, when partly immersed in water.

10. Why does it take some time to see objects in a dim room when you enter the room from bright sunlight outside?

In a dark room, if we try to see objects, the pupil will enlarge itself. So that more light enters it. If one suddenly goes into bright sunlight (or switches the bright light) one feels the glare. This is because too much light enters the enlarged pupil. Generally, the pupil contracts and things begin to appear normally.

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Things To Know For Handing A Sick Child

  

Nursing a sick child often requires more skill and understanding. The mind of a child works differently. He has no experience to guide him. A sick child is naturally afraid, even if you have told him he will be well again in a few days.

Child’s imagination: Every child has a highly active imagination, which becomes even more sensitive when he is sick. You must be careful not to increase his fears. Children have heard adults tell tales about illness and death, including all harrowing details. This sort of exaggeration is harmful to child. Then when he becomes ill, and his imagination is already working overtime, he may be almost scared to death. Therefore, try to keep him calm and quiet. Another instance of the fear in a child is the moment when the doctor prescribes an injection. If so, be sure to set a good example yourself. Don’t cringe when the doctor opens his bag. The child may be watching how you react in this emergency. If you are calm and cheerful, he will try to follow your example.

Fortunately, Nature is kind to young children. Most of their illness last only a few days at most. One minute they seem to be sick and at another they are up and running around as if nothing had happened. Except in certain crippling diseases, they rarely have to stay long in bed.

When your child is sick, be sure to consult the doctor early in the day. Don’t wait till midnight, merely hoping for the best. Remember, the earlier the doctor is consulted, the better for the child and also for yourself. A young child does not have the reserve energies of an adult. He can go downhill very rapidly with certain types of infection. Don’t take a chance, consult the doctor early.

Should you pamper your child? Not necessarily. All children like to be considered as heroes. So don’t pamper your child when he is sick. Sometimes they refuse to take prescribed diet and demand their choice. When this happens, try to explain the child how the planned and prescribed diet helps him become normal soon. Help him to act like a grown-up. At the same time do not make a simple illness seem too important. If your child gets too much attention, he may prefer to remain sick or feign sick.

Don’t allow too many visitors at home when your child is sick. Allow him to see Nature as much as possible. Narrate stories with happy endings. He may want to hear some favourite story over and over again. Either you read for him or narrate. Talk about cheerful things and avoid all morbid discussions. The child recovers fast and brings cheer in you.

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Know More About Wolves And Foxes And Their Species

The dog family includes wolves, foxes and jackals. The familiar domesticated dogs, which have been bred into a huge number of different shapes and sizes, probably originated from the grey or timber wolf. Unlike cats, dogs tend to hunt in groups, called packs. Their long, powerful legs enable them to run well and for long periods.

The common or grey wolf,  the largest of the dogs and found in forest, tundra and mountains, varies in appearance across its range. It is also called the timber wolf, steppe wolf, tundra wolf and plains wolf.

Wolves eat a wide range of food, from deer to small mammals and even berries and other fruits. Even though they are common in some places, wolves are very rarely a danger to people. There are 35 species of dogs and relatives. The thirty five species, including grey wolf, live in North America, Europe and across Asia.

Red wolf is found in south eastern North America and is exceptionally rare now. Coyotes are common in parts of North and Central America. They are rather like smaller versions of wolves and their strange night howls are the ‘call of the wild’. The maned wolf lives in tall grassland in South America. It has long, graceful legs and attractive red-brown hair. Like pet dogs, wolves put their ears back and bare their teeth when they feel in danger.

Four species of Jackals live in Africa, Southeast Europe and South Asia; Dingo is found in Australia. Dhole or Asian wild dog is found in India, China, and Southeast Asia; African wild dog is mainly found in Southern Africa.

21 species of Foxes are found worldwide except Australia. Red or Common Fox is one of the most adaptable and widespread of all mammals, living in remote country and also scavenging in towns and cities.

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