CN216411121U

CN216411121U - Device capable of accurately measuring liquid freezing point

Info

Publication number: CN216411121U
Application number: CN202122429000.1U
Authority: CN
Inventors: 王知非
Original assignee: Nanjing Feiwei Education Technology Co ltd
Current assignee: Nanjing Feiwei Technology Co.,Ltd.
Priority date: 2021-10-09
Filing date: 2021-10-09
Publication date: 2022-04-29
Anticipated expiration: 2031-10-09

Abstract

The utility model discloses a device capable of accurately measuring the freezing point of liquid, which comprises an aluminum shell container, a refrigerating sheet, a test tube and a thermometer, wherein the aluminum shell container is provided with a first opening and a second opening; the surface of the refrigeration sheet is slightly larger than the bottom of the aluminum shell and is used for placing a columnar aluminum shell container; the test tube is hung in a container with an aluminum shell; the test tube is used for placing liquid to be coagulated; suspending a thermometer in the liquid to be solidified; and a transparent observation window is arranged on the surface of the aluminum shell container. The device uses the even heating principle of two water baths for reference, simulates two water bath modes. The refrigeration sheet absorbs heat of saturated salt water in the aluminum container, and the saturated salt water absorbs heat of water in the test tube; the freezing point of the saturated salt solution is lower than the freezing point of water, and the water in the test tube is uniformly absorbed by the water bath to freeze the water, so that the temperature measurement and observation experiment phenomena are facilitated.

Description

Device capable of accurately measuring liquid freezing point

Technical Field

The utility model relates to the field of junior middle school physics teaching, in particular to a device capable of accurately measuring a liquid freezing point.

Background

In the physical teaching of junior high school, students usually need to know the physical phenomena and physical knowledge contained in the physical phenomena through some intuitive student experiments, and then the students are guided to think and research through exploring experiments. Therefore, the intuitiveness and the guidance of the experiment are important, and the experiment needs to be performed by using materials which are conveniently obtained at hand as much as possible. When the knowledge of melting and solidification is involved in teaching about the change of physical state in the physical experiment in junior high school, the crystal melting experiment is already available in the teaching material, but the experiment of solidification and how to measure the solidification point is not involved, because the experiment difficulty of measuring the solidification point is relatively large. Many teachers also try to give students an experiment of measuring the freezing point, the most common experimental method is shown in fig. 1, a thermometer A1 measures the temperature of water, and a refrigeration piece A4 absorbs the heat of a container A2; the refrigeration plate may not be needed if an ambient temperature significantly below the freezing point can be created. However, the error of the freezing point measured by the experiment is large and unstable, and the result of each time is different, which is easy to confuse students. For example, the most typical experiment is to measure the freezing point of water, but when the experiment is performed by using the device of fig. 1, the measured freezing point of water (the temperature of an ice-water mixture during the solidification) is common between 2 ℃ and 4 ℃, and the volume of a container, the position of a thermometer, the ambient temperature and the like can greatly influence the freezing point, so that the result of each experiment is different. We have found that the core of these problems is the non-uniform heating of the test object. During solidification, the thermometer actually measures substantially the temperature of the liquid, and the temperature of the solid is not easily measured. If the difference between the liquid and the overall average temperature at the bubble position of the thermometer is large, the true temperature of the freezing point is difficult to measure, and is usually high.

The prior art application number is: 201521004779, discloses the patent names: a metal cooling bath device in a freezing point determination experiment is characterized in that a metal cooling bath cup is embedded at the outer side of a beaker and wraps a semiconductor refrigeration sheet; the scheme is suitable for teaching with certain physical foundation in university education. For the junior and middle school students who just contact with physics, the academic requirement is high, and the students are easily distracted by complex structures such as a magnetic stirrer, a radiator and the like during experiments, but do not pay attention to the knowledge of the freezing point to be known. And because all there is the refrigeration piece parcel around, it is difficult to open transparent window for the student to observe the phenomenon in the icing process. Therefore, it is not suitable for teaching of junior middle school physics. There is therefore a need for an intuitive and simplified experimental apparatus for measuring the freezing point.

SUMMERY OF THE UTILITY MODEL

1. The technical problem to be solved is as follows:

the utility model provides a device capable of accurately measuring the freezing point of liquid, which can greatly improve the measuring precision of the freezing point of water or other liquids for solidification and ensure that the measuring results are very stable and reliable after multiple times.

2. The technical scheme is as follows:

an apparatus for accurately measuring the freezing point of a liquid, comprising: comprises an aluminum shell container, a refrigerating sheet, a test tube and a thermometer; the surface of the refrigeration sheet is slightly larger than the bottom of the aluminum shell and is used for placing a columnar aluminum shell container; the test tube is suspended in a container with an aluminum shell; the test tube is used for placing liquid to be coagulated; suspending a thermometer in the liquid to be solidified; and a transparent observation window is arranged on the surface of the aluminum shell container.

Further, the aluminum shell container is filled with saturated salt solution; the liquid to be coagulated in the test tube is water or other liquid with a coagulation point higher than that of saturated saline solution.

Furthermore, the refrigeration piece is connected with a power supply.

Further, the thermometer is a temperature sensor; the temperature sensor transmits the collected temperature information to the mobile terminal through wireless Bluetooth.

Further, the observation window is a transparent acrylic plate; the aluminum metal shell is provided with an acrylic plate groove; the acrylic plate and the acrylic plate groove are fixedly connected with the aluminum metal through waterproof glue.

3. Has the advantages that:

(1) this device borrows for reference the thermally equivalent principle of two water baths, the two water bath modes of simulation. The refrigeration sheet absorbs heat of saturated salt water in the aluminum container, and the saturated salt water absorbs heat of water in the test tube; because the freezing point of the saturated salt solution is lower than the freezing point of water, and the water bath uniformly absorbs the heat of the water in the test tube, the water in the test tube is uniformly and slowly frozen from all directions, and the temperature measurement and observation experiment phenomenon is convenient.

(2) The bottom of refrigeration piece to aluminium system shell container is cooled down in this experiment, and the liquid convection downwards that is low at the inside temperature of container, the hot liquid convection current that makes progress also causes the test tube to be heated inhomogeneously easily. Therefore, the device selects metal (aluminum) with good heat conductivity as the container wall.

(3) In the experiment, the phenomenon of supercooled water is easily caused when standing water is uniformly cooled, so that when the water temperature drops for the first time to break through 0 ℃ and reach-1 to-2 ℃, a thermometer needs to be stirred, and a glass stirring rod measured by a sensor is adopted in actual use to enable the water to start to solidify. Otherwise, after the temperature of the supercooled water is too low, the supercooled water is rapidly and completely solidified into ice, the solidification process is too short, the temperature is not changed, and the measured data is difficult to say.

(4) This device sets up transparent ya keli "window" on aluminum hull's surface, can directly perceivedly see the object state change phenomenon of water through this "window", has compromise the even and teaching show needs of being refrigerated.

Drawings

FIG. 1 is a schematic diagram of a prior art experimental apparatus for measuring the freezing point of water;

FIG. 2 is a schematic view of the apparatus of the present invention;

FIG. 3 is a top view of the present invention;

fig. 4 is a diagram of the phenomenon corresponding to the experiment of measuring the temperature of the temperature measuring liquid according to the embodiment.

Detailed Description

The present invention will be described in detail with reference to the accompanying drawings.

As shown in fig. 2 to 3, an apparatus for accurately measuring the freezing point of a liquid is characterized in that: comprises an aluminum shell container 2, a refrigerating sheet 4, a test tube 3 and a thermometer 1; the surface of the refrigeration sheet is slightly larger than the bottom of the aluminum shell and is used for placing a columnar aluminum shell container; the test tube is suspended in a container with an aluminum shell; the test tube is used for placing liquid to be coagulated; suspending a thermometer in the liquid to be solidified; the surface of the aluminum shell container is provided with a transparent observation window 5.

As shown in the figure, the schematic diagram of the glass bubble thermometer is taken as an example, and in practice, a temperature sensor with a wireless transmission function is usually selected in an experiment.

Furthermore, the refrigeration piece is connected with a power supply.

The specific embodiment is as follows:

as shown in fig. 4, the temperature of the freezing point and the melting point of water is measured by means of sensors and a corresponding experimental phenomenon graph, and the main experimental phenomena and results are as follows:

1. after the water is cooled to 0 ℃ for the first time, the liquid state is still kept.

2. When the temperature of the water is reduced to about-2 ℃, the water temperature is rapidly increased to 0.2 ℃.

3. The water begins to freeze, and the temperature is reduced from 0.2 ℃ to-0.3 ℃ through micro fluctuation in the process of completely freezing into ice. It was verified that the freezing point of water at normal pressure is 0 ℃.

4. If the cooling fins are closed during the freezing of the water, the water no longer freezes, but the ice present begins to melt. Indicating that the solidification of water requires an exotherm.

5. During the ice melting process, the temperature was raised from-0.1 ℃ to 0.1 ℃ with minor fluctuations. It was confirmed that the melting point of ice at ordinary pressure was 0 ℃.

6. During the melting of the ice, the temperature is substantially constant, while after the melting of the ice is completed, the temperature of the water is obviously and continuously increased. Indicating that the ice melts endothermically.

Although the present invention has been described with reference to the preferred embodiments, it should be understood that various changes and modifications can be made therein by those skilled in the art without departing from the spirit and scope of the utility model as defined by the appended claims.

Claims

1. An apparatus for accurately measuring the freezing point of a liquid, comprising: comprises an aluminum shell container, a refrigerating sheet, a test tube and a thermometer; the surface of the refrigeration sheet is slightly larger than the bottom of the aluminum shell and is used for placing a columnar aluminum shell container; the test tube is suspended in a container with an aluminum shell; the test tube is used for placing liquid to be coagulated; suspending a thermometer in the liquid to be solidified; and a transparent observation window is arranged on the surface of the aluminum shell container.

2. The device for accurately measuring the freezing point of liquid according to claim 1, wherein: saturated salt water is filled in the aluminum shell container; the liquid to be coagulated in the test tube is water or other liquid with a coagulation point higher than that of saturated saline solution.

3. The device for accurately measuring the freezing point of liquid according to claim 1, wherein: the refrigerating plate is connected with a power supply.

4. The device for accurately measuring the freezing point of liquid according to claim 1, wherein: the thermometer is a temperature sensor; the temperature sensor transmits the collected temperature information to the mobile terminal through wireless Bluetooth.

5. The device for accurately measuring the freezing point of liquid according to claim 1, wherein: the observation window is a transparent acrylic plate; the aluminum metal shell is provided with an acrylic plate groove; the acrylic plate and the acrylic plate groove are fixedly connected with the aluminum metal through waterproof glue.