Kids Questions & Answers

Frost is frozen moisture. It forms when invisible water vapour in the air changes directly from a gas-like state into ice crystals. In mountains, moisture in cracks in rocks freezes at night. Because ice occupies more space than water, the ice exerts a wedge like pressure inside the cracks, widening them until the rocks split. This is called frost action.

Remember walking to the school or the bus stop on a cold wintry morning? You can see the beautiful crystal drops of dew, and if you happen to be on the grass, they could well be soaking your shoes. Ever wondered why there is no dew in the summer or rainy seasons? Well, special as it looks, dew needs special …

For reasons of safe transportation of fruits, mangoes, bananas etc are picked before they ripen fully. Slightly green harvested mangoes are subjected to small containers of calcium carbide (CaC2) with a plastic covering. CaC2 reacts with the moisture in the air to release acetylene (or ethyne) gas, which like ethyleneis – a chemical substance produced by fruits to accelerate the …

Experiments by German scientists on the Sahara desert ant, called cataglyphis fortis, have shown that the ant uses a method known as ‘path integration’ in its navigation. Path integration consists of measuring the extent of each turn, and remembering the direction of its nest, whenever the direction of its path changes, and then measuring the distance of travel in each …

Even before submarines were thought about, Verne had created the blueprint of this technological marvel. Not only did he describe the machine, but he also explained, in great detail, how it worked. In fact, today’s submarines use exactly the same technology as Verne’s Nautilus did! How does a submarine float and dive under water at will? Try a little experiment. …

You may have noticed that an empty bottle will float along the surface of water, but one which is full of liquid will sink. The submarine works in exactly the same way. Each submarine has several large tanks, which can be filled with either water or air. When they were filled with air, the submarine will float on the surface …

Have you ever tried to prise apart the shell of a mussel or an oyster? It is practically impossible to do by just pulling, so how does the starfish manage it using only its tiny feet? The secret is that the starfish again uses its feet in relays. It hunches itself over the tightly closed shell and attached its tube …

The starfish and sea urchins creep slowly around on hundreds of hydraulically operated tube feet. If you flip a living starfish over you will see rows of these tiny feet running the length of each arm. (If you leave the starfish upside-down, time it to see how long it takes to turn itself the right way up again. Some can …

Snakes catch live animals and eat them whole. They can swallow prey several times larger than their head. This is made possible by very loosely jointed jaws which enable the mouth to be opened wide. Backward pointing teeth grip the prey while the mouth is worked over the animal. Lots of saliva helps the meal to slip down the snake’s …

Sea cucumbers are echinoderms that have a tough leathery skin rather than a spiny one. Lying around on the sea floor in tropical and subtropical countries they look rather like long fat sausages with tentacles at one end. They feed by poking the sticky tentacles around and then placing them one by one into the mouth. All the food fragments …