Surface tension experiment demonstration device

Abstract

The utility model relates to the technical field of teaching equipment, in particular to a surface tension experiment demonstration device which comprises a frame body, the frame body is provided with a platform, a tension demonstration unit and an adjusting device, the tension demonstration unit is located above the platform and comprises a cross beam, light springs are hung at the two ends of the cross beam, and the adjusting device is arranged on the platform. And an n-shaped wire is arranged at the bottom of the light spring. The n-shaped wire is put into the liquid, the surface tension of the liquid acts on the n-shaped wire, the n-shaped wire and the solution move relatively through the adjusting device, and in the moving process, the surface tension borne by the n-shaped wire acts on the light spring, so that the light spring deforms until the n-shaped wire is separated from the liquid level. Therefore, demonstration teaching of the surface tension experiment is carried out. The liquid surface tension demonstration device is reasonable in design, can demonstrate and compare the liquid surface tension under different liquid, different temperatures and different boundary line conditions, and is convenient for students to comprehensively understand the property of the liquid surface tension.

Description

Technical Field

[0001] The utility model relates to the technical field of teaching equipment, in particular to a surface tension experiment demonstration device. Background Art

[0002] Since all molecules in the surface layer of the liquid are subject to the gravitational force perpendicular to the liquid surface and pointing to the inside of the liquid, when the liquid is in a stable equilibrium state, the surface molecules of the liquid tend to squeeze into the liquid as much as possible to reduce the liquid surface as much as possible, making the liquid surface like a stretched membrane. This force that only exists on the surface of the liquid and makes the surface tend to shrink is called surface tension. Since different liquids have different molar volumes, molecular polarities and molecular forces, the surface tension is related to the type of liquid, temperature, length of the boundary line, etc.

[0003] The fourth section of the People's Education Edition of High School Physics Experiment Elective Three, "Surface Tension of Liquids", is a relatively abstract concept. In teaching, teachers can use experimental demonstrations to let students observe and feel the tension on the surface of liquids. By demonstrating the phenomenon that light objects such as paper clips and coins are placed on the liquid surface without sinking into the water, the properties and concepts of surface tension are introduced. Then, different teaching aids such as rectangular frames, circles, and meshes are used to demonstrate that liquids form unbreakable films, further explaining that there are forces on the surface of liquids. These teaching designs and teaching aids can help students understand the concept and properties of surface tension to a certain extent, but the demonstration content focuses on explaining the tension on the surface of liquids. There is not much demonstration and involvement of the different surface tensions of liquids with different liquids, different temperatures, and different boundary conditions, which is not conducive to students' in-depth understanding of the properties of liquid surfaces. Utility Model Content

[0004] The purpose of the utility model is to provide a surface tension experiment demonstration device to address the deficiencies of the prior art. The device is reasonably designed and can demonstrate and compare the surface tensions of liquids with different liquids, different temperatures and different boundary conditions, so as to facilitate students to further understand the properties of liquid surface tension.

[0005] The technical solution adopted by the utility model to solve its technical problems is: a surface tension experiment demonstration device, including a frame, the frame is provided with a platform for placing a container, a tension demonstration unit and an adjustment device for adjusting the distance between the platform and the tension demonstration unit, the tension demonstration unit is located above the platform, the tension demonstration unit includes a crossbeam, light springs are provided at both ends of the crossbeam, and a "∏"-shaped wire is provided at the bottom of the light spring.

[0006] Furthermore, the platform is movably connected to the frame, and the adjusting device is connected to the platform to drive the platform to move up and down.

[0007] Furthermore, the crossbeam is movably connected to the frame, and the adjusting device is connected to the crossbeam to drive the crossbeam to move up and down.

[0008] Furthermore, the adjusting device is a screw rod, one end of which is hinged to the crossbeam and / or the platform, such as a ball joint or a rotation connection.

[0009] Furthermore, the crossbeam or / platform is provided with a guide rod, and the guide rod passes through the frame and is movably connected to the frame.

[0010] Furthermore, the spring rates of the lightweight springs at both ends are the same.

[0011] Furthermore, along the vertical direction, the frame is provided with scale lines.

[0012] Further, when demonstrating the relationship between surface tension and boundary length, the lengths of the "∏"-shaped wires at both ends are not equal.

[0013] The beneficial effects of the utility model are as follows: a surface tension experiment demonstration device, comprising a frame, the frame being provided with a platform for placing a container, a tension demonstration unit and an adjusting device for adjusting the distance between the platform and the tension demonstration unit, the tension demonstration unit being located above the platform, the tension demonstration unit comprising a crossbeam, light springs being provided at both ends of the crossbeam, and a "∏"-shaped wire being provided at the bottom of the light spring. The "∏"-shaped wire is placed in a liquid, and the liquid and the "∏"-shaped wire form surface tension, and the distance between the tension demonstration unit and the platform is adjusted by the adjusting device. During the movement, the surface tension of the "∏"-shaped wire acts on the light spring, causing the light spring to deform, or the time when the "∏"-shaped wire is separated from the liquid surface, so as to carry out the demonstration teaching of the surface tension experiment. The existing surface tension demonstration experiment only demonstrates the existence of surface tension, and does not involve the factors affecting the size of the surface tension. The utility model is reasonably designed, and can demonstrate and compare the surface tension of different liquids, different temperatures, and different medium liquids, so as to facilitate students to further understand the properties of the surface tension of liquids. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural schematic diagram of the utility model.

[0015] Figure 2 yes Figure 1 main view.

[0016] Figure 3 yes Figure 2 Side view of.

[0017] Description of reference numerals:

[0018] 1——frame, 2——platform, 3——tension demonstration unit, 31——crossbeam, 32——light spring, 33——“∏” type wire, 4——adjusting device, 5——guide rod, 6——scale line. DETAILED DESCRIPTION

[0019] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments, but the scope of implementation of the present invention is not limited thereto.

[0020] It should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0021] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0022] like Figure 1 , Figure 2 and Figure 3 As shown, a surface tension experiment demonstration device of the present embodiment comprises a frame 1, wherein the frame 1 is provided with a platform 2 for placing a container, a tension demonstration unit 3 and an adjusting device 4 for adjusting the distance between the platform 2 and the tension demonstration unit 3, wherein the tension demonstration unit 3 is located above the platform 2, and the tension demonstration unit 3 comprises a crossbeam 31, wherein light springs 32 are provided at both ends of the crossbeam 31, and a "∏"-shaped wire 33 is provided at the bottom of the light spring 32, wherein the light spring 32 and the "∏"-shaped wire 33 are suspended above the platform 2 without contacting the platform 2, and the platform 2 is used for placing a container containing liquid, and the "∏"-shaped wire 33 of the tension demonstration unit is partially placed in the liquid.

[0023] The platform 2 is movably connected to the frame 1, and the adjusting device 4 is connected to the platform 2. By adjusting the lifting of the platform 2, the distance between the platform 2 and the "∏"-shaped wire 33 can be adjusted to demonstrate surface tension; or the beam 31 is movably connected to the frame 1, and the adjusting device 4 is connected to the beam 31. By adjusting the lifting of the beam 31, the distance between the platform 2 and the "∏"-shaped wire 33 can be adjusted to demonstrate surface tension.

[0024] The adjusting device 4 is a screw rod, which is hinged to the beam 31 and / or the platform 2, such as a ball joint or a rotating connection. The movement of the beam 31 or the platform 2 is driven by the screw rod, which is conducive to ensuring the smooth movement of the beam 31 or the platform 2.

[0025] The cross beam 31 or / the platform 2 is provided with a guide rod 5, and the guide rod 5 passes through the frame body 1 and is movably connected to the frame body 1, so as to facilitate the smooth up and down movement of the cross beam 31 or the platform 2.

[0026] The light springs 32 at both ends have the same stiffness coefficient, which is about 0.2 N / m. They can have a large elongation under a small external force, which is convenient for demonstrating surface tension.

[0027] In the vertical direction, the frame 1 is provided with scale lines to indicate the initial position of the light spring, and during the experimental demonstration, the change in the length of the light spring can be clearly reflected.

[0028] When demonstrating the relationship between surface tension and boundary length, the lengths of the "∏"-shaped wires 33 at both ends are not equal, so that the lengths of the "∏"-shaped wires 33 extending into the liquid are different, which is conducive to forming different boundary lengths; when demonstrating the surface tension phenomenon of different liquids and the surface tension phenomenon of the same liquid at different temperatures, the lengths of the "∏"-shaped wires 33 at both ends of the beam 31 are the same, that is, the lengths of the "∏"-shaped wires 33 extending into the liquid are the same.

[0029] The demonstration principle of the utility model is: Hooke's law F=k (L-L0). The spring will deform under the action of the internal external force of the elastic limit. If the stiffness coefficient k of the two springs is the same and the surface tension F is different, the deformation amount (L-L0) of the spring will also be different, and the change of surface tension is cleverly converted into the deformation of the spring.

[0030] When demonstrating surface tension, a container that can hold liquid is placed on the platform, and the "∏"-shaped wire 33 is extended into the liquid in the container. The distance between the platform 2 and the "∏"-shaped wire 33 is adjusted by the adjustment device 4, so that the "∏"-shaped wire 33 gradually detaches from the liquid surface in the container, thereby intuitively demonstrating surface tension.

[0031] The specific liquid surface tension experiment is demonstrated as follows:

[0032] 1. Demonstration of surface tension phenomena of different liquids.

[0033] Different liquids have different surface tensions. When the light spring is subjected to different tensions, the deformation amount is also different. The liquid in the left beaker on platform 2 is tap water, and the liquid in the right beaker is the same volume of ethanol, both at room temperature. The platform is slowly moved down by an adjustable screw or screw. During the downward movement, the liquid surface is slowly stretched, and the light spring is stretched. The tension of the light spring and the surface tension of the liquid are combined in the "∏" shape. Continue to move the platform down, the liquid film at the tap water end is broken slightly earlier, and the liquid film at the ethanol end is broken slightly later, indicating that the surface tension of different types of liquids is different.

[0034] 2. Demonstration of surface tension of the same liquid at different temperatures.

[0035] The beaker on the left side of the platform contains boiled water at room temperature, and the beaker on the right side contains the same volume of 60℃ warm boiled water. Slowly rotate the screw or screw under the platform to observe the time when the "∏"-shaped wire in the two beakers separates from the liquid surface. Through observation, it is found that the "∏"-shaped wire on the room temperature side separates from the liquid surface slightly earlier, and the "∏"-shaped wire on the 60℃ warm boiled water side separates from the liquid surface slightly later. This shows that the surface tension of the same liquid is different at different temperatures.

[0036] 3. Demonstration of surface tension of the same liquid at different boundary lines.

[0037] The two beakers on both sides of the platform contain boiled water of the same temperature and volume. "∏"-shaped wires of different lengths are hung under the light spring. The boundary line of the "∏"-shaped wire on the longer side is longer. The platform is slowly moved down through the adjustable screw or screw to observe the effect of different boundary lines on the surface tension. Through the observation of the phenomenon, it is found that the "∏"-shaped wire on the longer side leaves the liquid surface slightly later, and the "∏"-shaped wire on the shorter side leaves the liquid surface slightly earlier. This shows that the surface tension of the same liquid is different under different boundary lines.

[0038] When demonstrating the surface tension, the beaker is preferably a square beaker, which is convenient for sticking a magnifying glass on the outside of the beaker to observe the process of the "∏"-shaped wire leaving the liquid surface, especially the moment of leaving the liquid surface.

[0039] In addition, the device of the utility model can also be used to demonstrate or guide students to explore the influence of liquid purity and impurities on surface tension.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model, rather than to limit the protection scope of the utility model. Although the utility model has been described in detail with reference to the preferred embodiments, ordinary technicians in this field should understand that the technical solution of the utility model can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the utility model.

Claims

1. A surface tension experimental demonstration device, characterized in that: The invention comprises a frame (1), wherein the frame (1) is provided with a platform (2) for placing a container, a tension demonstration unit (3), and an adjustment device (4) for adjusting the distance between the platform (2) and the tension demonstration unit (3), wherein the tension demonstration unit (3) is located above the platform (2), and wherein the tension demonstration unit (3) comprises a crossbeam (31), wherein light springs (32) are arranged at both ends of the crossbeam (31), and a "∏"-shaped wire (33) is arranged at the bottom of the light spring (32).

2. A surface tension experimental demonstration device according to claim 1, characterized in that: The platform (2) is movably connected to the frame (1), and the adjustment device (4) is connected to the platform (2).

3. A surface tension experimental demonstration device according to claim 1, characterized in that: The crossbeam (31) is movably connected to the frame (1), and the adjustment device (4) is connected to the crossbeam (31).

4. A surface tension experimental demonstration device according to claim 1, characterized in that: The adjusting device (4) is a screw rod, and the screw rod is hinged to the crossbeam (31) and / or the platform (2).

5. A surface tension experimental demonstration device according to claim 1, characterized in that: The crossbeam (31) or / the platform (2) is provided with a guide rod (5), and the guide rod (5) passes through the frame (1) and is movably connected to the frame (1).

6. A surface tension experimental demonstration device according to claim 1, characterized in that: The spring rates of the lightweight springs (32) at both ends are the same.

7. A surface tension experimental demonstration device according to claim 1, characterized in that: Along the vertical direction, the frame (1) is provided with scale lines (6).

8. A surface tension experimental demonstration device according to claim 1, characterized in that: When demonstrating the relationship between surface tension and boundary length, the lengths of the "∏"-shaped wires (33) at both ends are not equal.

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