HOT OR COLD?
Many years ago when people had no thermometers, they usually touched a thing to see how hot or cold it was. The following experiment shows how easy it was to make a mistake. Take three glasses: one glass with very hot water, another glass with very cold water, and the third glass with water at room temperature. Then you put a finger of one hand in the hot water, and a finger of the other hand in the cold water. You hold your fingers in the two glasses for a minute. Then you use each finger, one after another, to see how hot or cold the water in the third glass is. You will find that the water is warm to the finger that was in the cold water before, but the finger which was in the hot water before will feel cold in the same glass of water. That is why you must always find the temperature in a scientific way. You must not try to tell the temperature as it seems to you.
You will often make a mistake if you take something that seems to you for a real fact. For example, when you are going to the circus by bus and you want to get there very quickly, it seems to you that your bus is going very slowly, slower than the other buses. But if it is Sunday and you have much free time, it seems to you that all the buses and cars are going very fast.
"MOSCOW IN THE SPRING"
If you looked at this triangle gle and read the words as "Moscow cow in the spring", please look at it again. The fact is that most people read a number of words at once; they do not read every word. That is why it is difficult for them to notice such mistakes like "the the" in the triangle. You will have a very good time if you show this triangle to your friends. Some of them will read it four or five times before they notice the second "the".
MOSCOW
IN THE THE SPRING
IT IS EASY TO REMEMBER SOME FACTS
Do you ever forget any important facts which you must remember? If you sometimes forget them, here are some examples which can teach you how to remember important facts and other things. Which side of a ship or airplane has a door for people to come in or to come out when the ship or airplane is at the port? You can remember that it is the left side if you look in front, because "left" and "port" have the same number of letters. Some teachers of mathematics in England remember ë to seven decimal places * because they remember the sentence, "May I have a large container of coffee?" The number of letters ters in each word stands for a figure of ë..
The picture which you see shows how your hands can help you to remember the number of days in each month. You imagine the names of the months on your knuckles and the places between them (from left to right). All the months which are on the knuckles have 31 days; the others have 30 days, except February. February, as you know, has 28 days, but once every four years, that is in leap-years, it has 29 days.
* to seven decimal places — äî ñåäüìîãî çíàêà