Question 1: Why is it important for us to eat some fatty food?
Answer 1: We need various vitamins as well as other nutrients, for the proper functioning of our bodies. Some of these vitamins are soluble in water, and will get absorbed by the intestine, even if there are no fats consumed. But vitamins A, D, E and K, do not dissolve in water. They dissolve in fats ( or lipids). So, if there are no fat molecules in the gut, vitamins A, D, E, and K might not get absorbed into the cells, and may just pass out of the body. Total absence of fats in the diet for a long time may even cause deficiency symptoms of the above vitamins!
Question 2: Why does unplanned removal of forest cover cause environmental problems?
Answer 2: Forests are home to wild animals – both small and large. So haphazard removal of forest cover in the name of development, would deprive us of natural habitats to so many plants and animals. Also, without forest cover, the surface water and most of the ground water, in a large area around the place gets destroyed, and dried up. In the long run, this will cause drying up of wells, lakes and rivers. if there is a fairly long period of drought. Before forest cover is removed, there should be a replanting program to supplement the plants that were cut down.
Question 3: How do astronauts keep cool in space?
Answer 3: The rays of the sun are much stronger in outer space, and therefore hotter. So astronauts need special ways of keeping cool. Under their space suits, they wear a suit of stretchy underwear, in which, tiny plastic tubes carrying cool water, run through. This water takes away the astronauts’ body heat to keep them cool.
Question 4: Why do my legs, or anything look shorter under water?
Answer 4: Water is a denser medium than air. So when light enters water from air, its rays travel more slowly through the denser water, than they do through air. This change in speed of light, causes the light rays to bend (or refract),so that the bottom of the body of water looks much higher than what it is!.
Question 5: Why can’t we see the moon on certain nights?
Answer 5: We can see any object only if light from that object reaches our eyes. For this, either that object must produce light, or if not, it has to reflect light falling on it. The Moon has no light of its own. So we see the moon only on nights when it faces the sun to reflect any light falling on it.
Question 6: How do most fish float at different levels in the water?
Answer 6: Many fish have a bag of air called the swim bladder inside their bodies. When the fish fills this bladder with air, it can float high in the water. Depending on how much of air is let out of this bladder, the fish can keep floating at different levels lower down.
Question 7: Why is sunlight warm whereas moonlight is not?
Answer 7: There are so many chemical reactions occurring in the sun, and most of these produce a vast amount of energy. Some of this energy is given out as light while some comes out as heat. These rays of heat travel towards the earth, and warm us up. Such energy producing reactions do not happen in the moon. So moonlight is not warm. Moonlight is really the light reflected from the surface of the moon.