Polarization of light is necessary for studying the optical properties of various substances.
It can be necessary and in a life - for example, by means of polarization of light it is possible to distinguish natural honey from counterfeit.
This phenomenon is also used in stereo photography and stereokino. Polarizing glasses are used by drivers of vehicles and polar explorers.
Several experiments can be done to study polarization, for example, in the physics lesson.
You will need
- 2 polarization filters
- Black polished wood or ebonite board
- Light source
- Sheet of white paper
Fold together 2 polarization filters. Direct them to the source Sveta. In this experience it should be a lamp or screen, but not the sun. Start rotating one filter relative to the other, looking through them at the source Sveta. At the same time, you will see how the image reaches its full brightness, then it fades away to almost complete extinction. The total brightness is observed when the polarization axes Sveta match. It is minimal when the polarization axes are perpendicular to each other.
Place a sheet of white paper on the table. Point the filters folded together in the sun so that the shadow from the filters lies on the sheet. Observe by shadow the change in the transparency of this optical design, depending on the position that one filter occupies relative to the other. As in the first case, the transparency will be the maximum when the polarization axes coincide, and is minimal when they are perpendicular.
Remove one of the filters. Repeat both previous experiences with one filter. Make sure that, regardless of its position, its transparency does not change.
Take a plate of polished wood or ebonite. Arrange it so that to observe on its surface a reflection from the source Sveta - for example, from the sun. Take the 1 polarizing filter. Consider reflection through it. Rotating the filter, observe the change in the brightness of the reflection. This experience shows that a dielectric mirror, in this case a polished sheet of ebonite or wood, polarizes the light, and the polarization axis lies in the plane of reflection. With a metal mirror, this experiment does not work.
As a source Sveta Apply a uniformly white-lit TV or monitor screen. Between the source Sveta And a polarization filter, add a band ofPlexiglas and, observing it through a polarizing filter, start bending it in different directions. At the same time, observe how multicolored lines and divorces appear in the thickness of Plexiglas. So under load transparent dielectric materials acquire the properties of changing the axis of polarization passing through them Sveta. This experience is used in the design of machine parts for the study of deformations under load. .