VIDEO: Radiation model in physics

The ray model of light

• Galileo Galilei was already thinking all his life about "what light actually is" (but could not find a conclusive answer). And also the modern one physics can only give a vague answer to this question for laypeople.
• Nevertheless, the ray model is one of the simplest models that physics knows for the phenomenon "light". And with this model, numerous everyday properties of light can also be explained casually.
• In this model, light sources such as candles, the sun or lamps send light straight into the room in all directions.
• Light emerges from openings as a so-called Light beam out.
• This propagation of light can be described with the help of straight lines, the rays of light. The starting point of such a light beam is a point of the light source.


Physics: Focus - Definition

"Focus" is a term from physics, more precisely from optics. Probably know ...

• An approximation for a (practically non-producible) light beam is a very narrow light beam.
• Through the beam of light is from the geometry given both the direction and the path of light.

Everyday phenomena of light - explained with the model from physics

Models are only really good if they contain important phenomena or Explain or can interpret. In fact, this is possible for a whole series of everyday experiments with light:

• Objects can only be seen by the observer when light rays from a light source hit it, are reflected there and then reach the observer's eye.
• The ray model is primarily used to explain the formation of shadows in physics, including solar and lunar eclipses.
• Surfaces reflect light rays according to the well-known law of reflection. Therefore, smooth surfaces can only reflect or reflect at certain angles. dazzle (also known from everyday life, for example from window panes or water surfaces).
• Light is refracted when it passes from one medium (e.g. air) to another (e.g. glass or water), i.e. the light beam is deflected from its original direction. The law of refraction in its mathematical form is an ideal idea for a ray of light.
• Rays of light can be used to explain the creation of the image with the pinhole camera, but also with mirrors and lenses. The law of reflection and the law of refraction are used.