The words we use seem to us familiar, familiar from childhood and understandable. It seems to us that we always know what we are talking about and what we mean. But if you try to find out from any passerby on the street, for example, the meaning of the word "ray", you can hardly count on a quick and correct answer. Indeed, what is it?
Etymology of the word
Let's start with the origin of this word. According to the dictionary of the Russian language, a beam is a stream of light that comes from some source, or a narrow strip of light coming from a luminous object. For example, the rays of the setting or rising sun.
The exact origin of the term is unknown, but presumably it originates from the Latin word for "light". In Slavic languages, this word is found everywhere. In Russian, it got their Old Slavonic.
Meaning and applications
The word "beam" is primarily associated with sunlight. How many times has everyone heard the expression: “sunbeams” or “ray of light”. But in fact, this word is directly related to geometry. A ray is a part of a straight line, which, on the one hand,one side is limited by a point, and on the other it is infinite.
Any ray has an extreme point. This is the beginning of the beam. Since it has no end, it is usually denoted by one letter. In addition, a ray is one of the simplest geometric shapes, such as a line segment or a broken line.
The concept of a beam is also used in physics, but only in acoustics and geometric optics. Here the beam is the line along which the light energy moves.
The main feature of the geometric and light beam is their straightness. But for light this is true only if it propagates in a homogeneous transparent medium. Otherwise, it becomes curvilinear.
How to see the light
Children will love this experience, it will show them what a beam of light is. This requires some simple preparation. You need to darken the room and put any flashlight on the edge of the table. The beam of light is now barely visible, but as soon as you sharply squeeze a pre-prepared plastic bottle with talc or baby powder, the powder particles, once in it, begin to glow. Now children can see that the light beam is a streak of light coming from a flashlight and continuing to infinity. Why is this happening? The fact is that light cannot be seen until it is reflected from some surface. Talc particles, hitting a beam of light, make it clearly visible.
