Category Archives: WHAT?
50.WHAT ARE BACTERIA?
Man’s relationship to bacteria is a very interesting one. We all know that many bacteria are harmful. Diseases such as typhoid fever, cholera, diphtheria, pneumonia, and all infections that occur in open wounds are each caused by a particular kind of bacteria. So man wages war on these bacteria.
Yet, without the action of other types of bacteria, life would be impossible on earth! In fact, man actually cultivates certain bacteria because he needs and uses them.
41.WHAT WOULD HAPPEN WHEN THERE IS NO DUST?
Would the world really be so much better off if there were no dust? The answer is: in some ways—yes; in some ways—no. What is dust, anyway? It consists of particles of earth, or other solid matter, which are light enough to be raised and carried by the wind. Where do these particles come from? They might come from dead plant and animal matter, from sea salt, from desert or volcanic sand, and from ashes or soot.
For the most part, dust is not a very desirable or beneficial thing. But in one way, it helps make the world more beautiful! The lovely colors of the dawn and of twilight depend to a great extent on the amount of dust that is present in the air.
40.WHAT IS THE ATMOSPHERE OF THE EARTH?
As we read about man’s plans to explore the moon and other planets, we often come across the question of an atmosphere. Do other planets have an atmosphere, too?
As far as scientists know, there is no other planet or star that has an atmosphere like ours. What is atmosphere? We can think of it as a great ocean of air that surrounds the earth and that extends up for hundreds of miles.
