JPH0396984A - Refraction experimentation device for optical path by gas layer having density gradient - Google Patents

Abstract

PURPOSE:To enable visnal inspection for the bending of an optical path due to a temperature difference in air by providing a heating tube body at the upper part of a tube body provided with a light guide-out window and also providing a cooling tube body opposite at the lower part of the tube body, and providing a light source which emits light into the tube body. CONSTITUTION:The heating tube body A is provided at the upper part of the tube body C which is provided with a light guide-in window D where light is made incident at one end and the light guide-out window W where light is guided out at the other end, and the cooling tube body B is provided at the lower part of the tube body. Then the light source K which emits light into the tube body C is provided from outside the tube body C. For example, high-temperature steam C is sent in the heating tube body A provided at the upper side of the tube body C and cooling water W is run through the cooling tube body B provided opposite on the lower side of the tube body C to form a high-temperature side and a low- temperature side in the vertical direction of gas H in the tube C, thereby generating the density gradient in the vertical direction of the gas H. When the light source K emits the light through the light guide-in window D in this state, the high-temperature side and low- temperature side differ in refractive index, so the emitted light is refracted and emitted from the light guide-out window E. This emitted light is projected on a screen, etc., to measure the extent of refraction quantitatively.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This device relates to an experimental device for refraction of an optical path by a gas layer with a density gradient, which is used for physics education in high schools, technical colleges, and universities. be.

[Problems that Jubei's technology and inventions aim to solve]

Until now, no educational experimental device has been proposed that can confirm that an optical path is bent due to refraction and can quantitatively explain the concavity of refraction.

The present invention provides an optical path refraction experimental device using a gas layer with a density gradient, which makes it possible to quantitatively experiment and explain the refraction of light by creating a vertical density gradient in the gas due to a temperature difference. It is something.

[Means to solve the problem]

The present invention will be described below with reference numerals used in the drawings for easy comparison with the drawings showing an example of implementation.

A heating tube 8 is provided on the upper side of the tube C, which has a light introduction window D for introducing light at one end and a light emitting window E for guiding light at the other end, and a cooling tube 8 is provided for the lower side of the tube C. This relates to an optical path refraction experimental device using a gas layer with a density gradient, characterized in that a body B is disposed opposite to the outer tube body C, and a light source K is provided for irradiating light into the outer tube C from outside the tube C. .

2. The optical path refraction experimental device using a gas layer with a density gradient as claimed in claim 1, characterized in that an inlet cock G and an outlet cock F are provided for replacing the gas I-■ in the tube body C with another gas. This is related to.

[For production]

For example, high-temperature steam S is passed through the heating tube A provided above the tube C, and cold water W is passed through the cooling tube B provided opposite to the bottom of the tube C, thereby reducing the gas in the tube C 4. A high temperature side and a low temperature side are created in the vertical direction, and a density gradient is created in the vertical direction of the gas I-{.

In this state, light introduction window D. 1) When light is irradiated from the light source K, the refractive index on the high temperature side, that is, the side with low density on the side of the heating tube A is different from the refractive index on the side of the cooling tube B, that is, the low temperature side, that is, the side with high density. The emitted light does not travel straight, but is refracted and emitted from the light guide window E.

By capturing this emitted light on a screen I, for example, the degree of refraction can be quantitatively measured.

In addition, when performing a comparative experiment by replacing gas 1 in tube C with another gas, derive gas 1 from derivation cock F, and introduce another gas from introduction cock G to replace it. .

〔Example〕

An embodiment of the invention is shown in FIG. In this device, a heating metal pipe A is installed on the upper side inside a thick tube body C made of glass or acrylic, and a cooling metal pipe B is installed oppositely on the lower side inside this tube body C. This is a device in which a light introduction window D is provided at one end (the left end in the drawing) and a light exit window E is provided at the other end (the right end in the drawing), and each window DE is closed with a glass plate.

The heating metal pipe A is heated by passing high-temperature steam S from a steam generator or an electric current is passed through a linear heater installed inside, and the cooling metal pipe B is cooled by passing cold water W. By not allowing the temperature difference ΔT to appear below the air layer, a density difference Δd is stably created in the air layer below the air layer.

Further, when experimenting with the refraction of light due to a gas other than air or a gas mixture with air, the introduction cock G and the output cock F are opened to replace the gas H. In the drawing, the outlet cock F and the inlet cock G are shown in the lower part for easy understanding, but the same effect can be obtained even if they are provided on the side 34- of the tube body C.

A laser beam irradiated from a light source K through a light introduction window D at one end is refracted by the density gradient of internal air (or introduced gas) H, and is emitted from a light exit window E at the other end.

As shown in FIG. 2, the refracted angle Δθ is measured by the amount of movement ΔXj of a light spot J on a screen placed several meters away from the apparatus.

In FIGS. 1 and 2, the inclination angle (incident angle) φ with respect to the central axis O of the optical path, the bending angle Δθ of the optical path, etc. are exaggerated. Further, the entire apparatus shown in FIG. 2 is an example of an open type in which the glass plates of the windows DE at both ends for leading out and introducing light are omitted. This device can also measure the bending of the optical path due to air.

(Figure 1 is an example of a closed type.) [Quantitative explanation of refraction in experiments using this device] The temperature on the high temperature side is T, and the refractive index is n. The temperature on the low temperature side is T2, and the refractive index is n2. When the inclination angle (incident angle) φ from the horizontal axis (center axis 0) of the optical path is small, if the incident angle is θ and the refraction angle is 02 as shown in Figure 3, then according to the law of refraction, the refractive index is The ratio is as follows, and from the measured values of φ and Δθ, the ratio of the refractive index n,, n1,
Or the difference in n, h, and the temperature difference Δ between the upper and lower air layers
T is evaluated.

Examples of measurement data when the high temperature side is heated with steam S and the low temperature side is cooled with normal tap water W are shown below.

In Figure 2, Distance from the center of the device to screen I, L =
3.66m ・Length of tube C of the device, ]=90cm ・Diameter (inner diameter) of tube C, 35mmφ ・Amount of movement of laser spot on screen I
Δx=7.8mm ・Wavelength of laser light, λ = 632.8nm ・Temperature of upper part of light introduction part tube, t,=51.8℃ T=324.8K ・Temperature of lower part of light introduction part tube, t,=27.4 °C T , = 300.4K - Inclination angle of the optical path from the horizontal axis (central axis O), φ = I. I
2X 10-'rad ・Refraction angle of optical path ([111 angle from optical axis), Δ0
= 2 08
lO-' or difference in refractive index, np 11,= n,/r++ l= 2.5
X 10-5 On the other hand, the ratio of the refractive index determined from the temperature difference is, however, in the case of air, k = 7.96X 10-' (
K, and a quantitative explanation can be given.

Next, air and other gases (e.g. carbon dioxide)] The bending angle of the optical path, Δθ9 and Δθ, respectively.

By measuring , the difference in refractive index between two gases can be evaluated.

Since the refractive index of air, nA-I0kA/T and the refractive index of carbon dioxide gas, nc"' I + kc/T (where r = 80./ΔθA), the angle of the bend is The difference in refractive index can be evaluated from the ratio Δθ./Δθ3.

Conversely, the difference in refractive index can be visually displayed by this device as a difference in the amount of movement ΔX of the spot.

〔Effect of the invention〕

By using this device in educational experiments, it is possible to easily and quickly simulate phenomena in the laboratory where optical paths are bent due to temperature differences in the air, such as astronomical refraction caused by the atmosphere, geomirror phenomena on asphalt road surfaces, and parasitic phenomena. It becomes possible to visually display the time.

8 In addition, it becomes possible to quantitatively explain the explanation from the law of refraction.

[Brief explanation of drawings]

FIG. 1 shows an experimental apparatus for refraction of an optical path by an air layer having a density gradient according to an embodiment of the present invention. FIG. 2 is an overall layout diagram for measuring refraction of an optical path using this device. Figure 3 shows the incident angle θ1, refraction angle θ, and φ, Δ according to the normal law of refraction.
FIG. 3 is an explanatory diagram showing the relationship between θ. September 8, 1st year of Heii

Claims (1)

[Scope of Claims] 1. A heating tube is provided on the upper side of a tube which has a light introduction window for introducing light at one end and a light output window for guiding light at the other end, and a cooling tube is provided at the lower side of the tube. What is claimed is: 1. An optical path refraction experimental device using a gas layer with a density gradient, characterized in that a light source is provided to irradiate light into the tube from outside the tube. 2. The optical path refraction experimental device using a gas layer with a density gradient according to claim 1, further comprising an inlet cock and an outlet cock for replacing the gas in the tube with another gas.