Teaching device for combustion three-factor contrast experiment

Abstract

The utility model provides a teaching device for a combustion three-factor contrast experiment, which is characterized in that the teaching device comprises a water tank (1) and a three-branch test tube (2) capable of being inserted into the water tank (1), the three-branch test tube (2) comprises a main tube (2a), one end of the main tube (2a) is communicated with a right branch tube (2b), a middle branch tube (2c) and a left branch tube (2d), and an opening at the other end of the main tube (2a) is provided with a plug cover (3). A gas pipe (4) and an oxygen detector (5) are arranged, one end of the gas pipe (4) is inserted into the main pipe (2a) through a plug cover (3), the other end of the gas pipe (4) is communicated with the oxygen detector (5), and a correspondingly matched ventilation control structure (6) is arranged on the gas pipe (4). The blackboard eraser is simple in structure and convenient to use, no toxic substance escapes when the blackboard eraser is used, harm to the bodies of teachers and students is reduced, and meanwhile the environment is protected.

Description

TECHNICAL FIELD

[0001] The utility model relates to teaching aids field, concretely is a kind of teaching device for burning three-factor comparison experiment. BACKGROUND

[0002] Based on the content of the experiment 7-1 in the 128th page of the first volume of the ninth-grade chemistry textbook of People's Education Press is: "in 500ml beaker, add 300ml hot water, and put a small piece of white phosphorus circled by hard paper ring. A small amount of oxygen is introduced into the white phosphorus in the beaker by a catheter, and the phenomenon is observed. The purpose of this experiment is to explore the conditions required for the combustion of combustible materials by observing the combustion of white phosphorus.

[0003] Combustion of combustible material involves three key elements: combustible material, combustion-supporting gas (such as oxygen) and ignition point. In the three-element experiment comparison in the textbook, white phosphorus burns in an open environment, producing a large amount of toxic white smoke (P2O5) that spreads in the classroom, which cannot be effectively absorbed and treated. If inhaled, it will cause harm to the human body, and its discharge into the environment will also affect the safety of the ecological environment. The key is that in teaching, the experiment is still demonstrated under the condition that the white smoke (P2O5) is toxic, which cannot arouse students' attention to the safety of the ecological environment, and has a negative imitation effect on students, which is seriously inconsistent with the green concept of low-carbon environmental protection advocated by the state.

[0004] However, in order to deepen students' understanding of the conditions of combustion, on-site demonstration is indeed necessary. Based on this, by analogy, it is necessary to develop a teaching device that can be used for three-factor comparison experiment, ensure that toxic gas does not leak, and can absorb toxic gas for harmless treatment. TECHNICAL CONTENT

[0005] The utility model is to overcome the deficiency in the prior art, and provide a teaching device for three-factor comparison experiment of combustion.

[0006] The present application provides the following technical solutions:

[0007] A teaching device for three-factor comparison experiment of combustion, characterized in that it comprises a water tank, hot water is arranged in the water tank, a three-pronged test tube is arranged in the water tank, the three-pronged test tube comprises a main pipe, a right branch pipe, a middle branch pipe and a left branch pipe are communicated at one end of the main pipe, a plug is arranged at the opening of the other end of the main pipe, a catheter is arranged in the main pipe, a gas pipe and a measuring instrument are arranged, one end of the gas pipe is communicated with the catheter inside and outside the main pipe, the gas pipe is inserted into the main pipe through the plug, the other end of the gas pipe is communicated with the measuring instrument, and a corresponding air control structure is arranged on the gas pipe.

[0008] On the basis of the above technical solutions, the following further technical solutions can also be provided:

[0009] The ventilation control structure is a manual valve body or a clamp, and the clamp is an existing water stop clamp or a long-tail clamp or a stainless steel file folder.

[0010] The water tank is a tank body made of flat-bottomed transparent material, and the transparent material is glass or plastic or acrylic.

[0011] The lower ends of the right branch pipe, the middle branch pipe and the left branch pipe are in the same horizontal plane, so that the lower ends of the right branch pipe, the middle branch pipe and the left branch pipe can stably contact the tank bottom surface.

[0012] The measuring instrument is an oxygen measuring instrument or a carbon dioxide measuring instrument or a temperature measuring instrument.

[0013] The temperature of the hot water is 70-90 DEG C.

[0014] The utility model has the advantages of simple structure, convenient use, can realize observation based on three-factor condition experiment under the condition that the external environment is consistent, also realizes online measurement of monitoring target components in a sealed environment, presents experiment exploration to students in a scientific and intuitive way.

[0015] The utility model has the advantages of simple structure, convenient use, can realize observation based on three-factor condition experiment under the condition that the external environment is consistent, also realizes online measurement of monitoring target components in a sealed environment, presents experiment exploration to students in a scientific and intuitive way. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 It is the structural schematic diagram of the utility model. DETAILED DESCRIPTION

[0017] As Figure 1 shown, a kind of teaching device for burning three-factor contrast experiment, it includes transparent glass made water tank 1, in water tank 1, add 80 DEG C hot water 1a.

[0018] Three-pronged test tube 2 can be inserted in water tank 1 is set, three-pronged test tube 2 includes main pipe 2a, and the lower end of main pipe 2a is communicated with the bottom sealed right branch pipe 2b, middle branch pipe 2c and left branch pipe 2d.The lower ends of the right branch pipe 2b, the middle branch pipe 2c and the left branch pipe 2d are in the same horizontal plane, so that the lower ends of the right branch pipe 2b, the middle branch pipe 2c and the left branch pipe 2d can stably contact the tank bottom surface.This way when three-pronged test tube 2 is inserted in water tank 1, the lower ends of right branch pipe 2b, middle branch pipe 2c and left branch pipe 2d can be soaked in the water layer of the same temperature, ensure that the temperature of each pipe lower end is consistent.

[0019] A plug 3 is provided at the opening of the upper end of the main tube 2a. A glass conduit 3a is vertically provided in the plug 3, and the lower end of the conduit 3a is inserted into the main tube 2a by a certain length. A rubber air tube 4 and an oxygen measuring instrument 5 are provided, and a water stop clamp is connected to the air tube 4 by a tethering manner, serving as a ventilation control structure 6 of the air tube 4, i.e. the ventilation of the air tube 4 is controlled by the water stop clamp. One end of the air tube 4 is in communication with the upper end of the conduit 3a located outside the main tube 2a, and the other end of the air tube 4 is in communication with the detection nozzle of the oxygen measuring instrument 5.

[0020] Usage process:

[0021] Preparation of experiment:

[0022] At room temperature (below 30 degrees Celsius), white phosphorus and water are put into the right branch tube 2b, and the white phosphorus is completely immersed in the water. White phosphorus is put into the middle branch tube 2c, and red phosphorus is put into the left branch tube 2d. Then the plug 3 provided with the air tube 4 is inserted into the opening of the main tube 2, so as to make the main tube 2 airtight. The oxygen content in the trifurcated test tube 2 is detected by the oxygen measuring instrument 5 and the value (21%) is recorded, and then the air tube 4 is clamped by the water stop clamp, so that the air tube 4 is in a non-ventilation state.

[0023] 2. Experiment 1) stage:

[0024] The lower end of the trifurcated test tube 2 is inserted into the hot water in the sink 1, so that the lower ends of the right branch tube 2b, the middle branch tube 2c and the left branch tube 2d are immersed in the hot water and are in the same water layer. Under the action of the hot water, the white phosphorus in the middle branch tube 2c quickly reaches the ignition point (40°C) and burns completely, while the white phosphorus in the right branch tube 2b cannot contact with the oxygen in the air in the trifurcated test tube 2 due to the water barrier, so it cannot burn even if it is at the ignition point. The red phosphorus in the left branch tube 2d has a higher ignition point (240°C), so even if it can contact with the oxygen in the air in the trifurcated test tube 2, it cannot burn.

[0025] 3. Experiment 2) stage:

[0026] When the white phosphorus in the middle branch tube 2c is burned out, the trifurcated test tube 2 is taken out of the sink 1, and then the trifurcated test tube 2 is tilted so that the water in the right branch tube 2b flows into the middle branch tube. At this time, the white phosphorus (temperature reaches the ignition point) originally located in the right branch tube 2b is exposed from the water and contacts with the oxygen in the air in the trifurcated test tube 2, and then it burns spontaneously, but the burning flame is obviously smaller than that in the previous experiment stage. At this time, the oxygen content in the trifurcated test tube 2 has been greatly reduced due to the previous burning.

[0027] The white phosphorus after spontaneous combustion is quickly extinguished, so that the white phosphorus in the right branch tube 2b cannot burn out, because the oxygen content in the trifurcated test tube 2 has been reduced to a level that cannot support the burning of white phosphorus, so the white phosphorus will extinguish itself.

[0028] 4、Experiment 3)stage:

[0029] Remove the water stop clamp so that the trachea 4 back into the ventilation posture, through the oxygen meter 5 detection of oxygen content in the three-pronged test tube 2 (11.6%). It can be seen that the white phosphorus is not extinguished because the oxygen in the three-pronged test tube has been exhausted, but because the oxygen content in the three-pronged test tube is below a certain concentration, it cannot support the required combustion, and the white phosphorus will extinguish itself.

[0030] Thus, it can be directly shown that the three factors of combustion are: combustible material, combustible material temperature reaching the ignition point, and oxygen content in the environment where the combustible material is located reaching the concentration that supports combustion. None of the three is dispensable.

Claims

1. A teaching device for a three-factor comparative experiment for combustion, characterized in that: It includes sink (1), be equipped with hot water in sink (1), set up a three-pronged test tube (2) that can be inserted into sink (1), three-pronged test tube (2) includes main pipe (2a), right branch pipe (2b), middle branch pipe (2c) and left branch pipe (2d) are communicated at main pipe (2a) one end end, be equipped with plug cover (3) at the opening of the other end of main pipe (2a), be equipped with the catheter (3a) that one end is inserted into main pipe (2a) at plug cover (3), set up air pipe (4) and measuring instrument (5), air pipe (4) one end with catheter (3a) communication, air pipe (4) other end with measuring instrument (5) communication, set up corresponding air control structure (6) on air pipe (4).

2. The teaching device for burning three-factor contrast experiment according to claim 1, characterized in that: The air control structure (6) is a manual valve body or a clip.

3. The teaching device for burning three-factor contrast experiment according to claim 1, characterized in that: The sink (1) is a flat-bottomed sink body made of a transparent material, and the transparent material is glass or plastic or acrylic.

4. The teaching device for burning three-factor contrast experiment according to claim 1, characterized in that: The lower ends of the right branch pipe (2b), the middle branch pipe (2c), and the left branch pipe (2d) are on the same horizontal plane, so that the lower ends of the right branch pipe (2b), the middle branch pipe (2c), and the left branch pipe (2d) can stably contact the sink (1) bottom surface.

5. The teaching device for burning three-factor contrast experiment according to claim 1, characterized in that: The measuring instrument (5) is an oxygen measuring instrument or a carbon dioxide measuring instrument or a temperature measuring instrument.

6. The teaching device for burning three-factor contrast experiment according to claim 1, characterized in that: The temperature of the hot water is 70-90°C.

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