CN111915969A

CN111915969A - Plant photosynthesis teaching experiment method

Info

Publication number: CN111915969A
Application number: CN202010726905.2A
Authority: CN
Inventors: 黄小娜; 杨继富; 石威廉
Original assignee: Qiannan Normal University for Nationalities
Current assignee: Qiannan Normal University for Nationalities
Priority date: 2020-07-26
Filing date: 2020-07-26
Publication date: 2020-11-10

Abstract

The invention discloses a plant photosynthesis teaching experiment method. Marking experimental containers, namely marking 3 experimental containers with the same specification; b. weighing algae: respectively putting equal weight of algae in two of the marked experimental containers; c. solution dilution and split charging: dripping the litmus solution into clear water to prepare a purple litmus solution; subpackaging the purple litmus solution into two parts, wherein one part is directly sealed, and the other part is introduced with carbon dioxide gas to change the purple litmus solution into a red solution, stopping introducing the gas and sealing; d. pouring litmus solution: filling one experimental container filled with algae with directly sealed purple litmus solution; filling the other two marked experimental containers with red solution; e. illumination: the 3 labeled test containers were placed under daylight illumination. The method has the characteristics of simple experimental device and steps, less reagent use, good air tightness, obvious experimental phenomenon, environmental protection and good safety.

Description

Plant photosynthesis teaching experiment method

Technical Field

The invention relates to a biological course teaching experiment, in particular to a plant photosynthesis teaching experiment method.

Background

Biology is a natural science based on experiments, so the research experiment plays an important role in biological teaching. Biological experiments are an important method for biological science research and are the basis for biological science development; biological experiments are also the best mode for culturing the innovation consciousness of students, and are irreplaceable ways for promoting the comprehensive development of comprehensive qualities of the students. Can help the student to build knowledge through the experiment, deepen understanding and the grasp to the problem, can also arouse student's learning passion, improve scientific quality.

The inventor finds that ' carbon dioxide in the fifth unit chapter ' carbon-oxygen balance in green plants and biosphere ' of the seventh grade of the third unit of the seventh edition of biological teaching material of human education? The exploratory experiments of'' have the following disadvantages:

the experimental device is complex and has more reagents. The experimental device mainly comprises a dark treatment device, a sealing device, an alcohol lamp device and a rinsing device; the experimental reagent mainly comprises sodium hydroxide solution, vaseline, water, alcohol and iodine solution.

② the experimental steps are complex and the experimental time is long. Sodium hydroxide and an alcohol lamp are used in the experimental process, so that potential safety hazards exist, the operation needs to be very careful, and in addition, the complex processes of assembling, decoloring, rinsing and the like of the sealing device need to be guided by teachers in the whole process, so that certain difficulty is brought to the study of students and the teaching of teachers; dark treatment needs one day and night or 2-3d, illumination time is 2-4h, alcohol decoloration needs about 10min, the whole experiment is long in time consumption, the teaching of teachers is not facilitated, more learning time of students is occupied, and students with more subjects to be learned in junior and middle school stages are not facilitated.

③ the test was not hermetic (see FIG. 1). Placing the beaker filled with the geranium branches into a small water tank, then placing the small water tank into a large plastic bottle cap, covering the large plastic bottle cap with a transparent plastic bottle, screwing the small water tank tightly, and coating vaseline on the bottle mouth so as to prevent air from leaking into the small water tank due to uneven sealing, wherein if the small water tank is not operated properly, the air leaking into the small water tank can influence the experimental result; the requirement on the sealing performance is high, and the first student has certain difficulty in operating by hands.

And fourthly, the experimental phenomenon is not obvious. Since a large plastic bottle is used for covering to form a closed space, the content of carbon dioxide in the device is limited, photosynthesis is affected, and the amount of starch produced is reduced. In addition, if the pigment is not completely decolorized, the interference of chlorophyll can exist, and the experimental phenomenon is not obvious.

Waste of resources and environmental pollution. The leaves of the geranium used as the material die after being heated, so the experimental value is lost, and the cyclic utilization cannot be realized; in the experiment, a large amount of alcohol and sodium hydroxide are used, so that resource waste and environmental pollution are caused.

The experimental materials are not easily obtained. Most of the pelargonium roseum is maintained indoors, and when the pelargonium roseum is moved to strong light, the pelargonium roseum wilts quickly, grows slowly, has limited quantity, is fragile and easy to fall, and is difficult to meet the requirements of grouping experiments.

In addition, the biological experiments have high requirements on experimental facilities such as experimental appliances, experimental sites and the like, and some school conditions still cannot meet the requirements for carrying out the experiments, so that the popularization of experimental teaching is not facilitated.

Disclosure of Invention

The invention aims to provide a plant photosynthesis teaching experiment method. The method has the characteristics of simple experimental device and steps, less reagent use, good air tightness, obvious experimental phenomenon, environmental protection and good safety.

The technical scheme of the invention is as follows: a plant photosynthesis teaching experiment method is carried out according to the following steps:

a. marking the experimental containers, namely marking 3 experimental containers with the same specification;

b. weighing algae: respectively putting equal weight of algae in two of the marked experimental containers;

c. solution dilution and split charging: dripping the litmus solution into clear water to prepare a purple litmus solution; subpackaging the purple litmus solution into two parts, wherein one part is directly sealed, and the other part is introduced with carbon dioxide gas to change the purple litmus solution into a red solution, stopping introducing the gas and sealing;

d. pouring litmus solution: filling one experimental container filled with algae with directly sealed purple litmus solution; filling the other two marked experimental containers with red solution;

e. illumination: placing 3 marked experimental containers under a fluorescent lamp for illumination;

f. and observing and recording experimental phenomena.

In the step a of the experimental method for teaching plant photosynthesis, the experimental container is a small conical bottle of 50 ml.

In the step b of the above teaching experiment method for plant photosynthesis, the weight of the algae put into each experiment container is 20 g.

In the step c of the teaching and experimental method for plant photosynthesis, the carbon dioxide gas is prepared by reacting limestone with sufficient diluted hydrochloric acid.

In step e of the plant photosynthesis teaching experiment method, the illumination specifically comprises: the 3 labeled test containers were placed in a 25cm light for 4min from a 100W fluorescent lamp.

Compared with the prior art, the invention has the following beneficial effects:

the experimental device is simple (see figure 2), and the reagent is less. As shown in FIG. 2, the experimental device of the present invention mainly comprises instruments commonly used in laboratories, and mainly comprises a beaker, a conical flask and a lighting device. The reagents used included: small amount of limestone, dilute hydrochloric acid, clear water and litmus solution.

And the experimental steps are simple, and the time is short. The experimental steps of the invention mainly comprise marking a small conical flask, weighing algae, diluting and subpackaging solution, injecting litmus solution, illuminating, observing and recording experimental phenomena; the experiment operation is simple, and the whole experiment consumes about 30 min.

And thirdly, the experimental air tightness is good. Because each conical flask has a rubber plug, the air-tight and air-tight effects are achieved.

And fourthly, the experimental phenomenon is obvious. As carbon dioxide and water react to form carbonic acid; the purple litmus solution shows red when meeting carbonic acid; the green leaf plants carry out photosynthesis to absorb carbon dioxide so that the red litmus solution is changed into purple litmus solution; the solution color change is evident.

Fifthly, resources are not wasted, and environmental pollution is not caused. The algae can be put back to nature again when used for experiments; the dilute hydrochloric acid used in the experiment reacts with limestone to become salt, and no pollution is generated to the environment.

Sixthly, the safety is good. The reagent of the experiment of the invention is litmus solution which is organic acid, has no corrosivity and has no great potential safety hazard.

In conclusion, the invention has the characteristics of simple experimental device and steps, less reagent use, good air tightness, obvious experimental phenomenon, environmental protection and good safety.

In order to verify the beneficial effects of the present invention, the inventors compared the original experimental operation and the experimental operation of the present invention as follows:

1 Experimental teaching implementation before and after improvement

The teaching objects before and after the experiment improvement respectively select the whole students of 4 classes and 5 classes of the seven-grade middle school of east town of city big park, wherein 4 classes choose to use the original experiment for teaching, and 5 classes choose to use the replacement experiment for teaching. Each shift was divided into 8 groups, 8 groups for 4 shifts were A, B, C, D, E, F, G, H groups, and 8 groups for 5 shifts were a, b, c, d, e, f, g, h groups. The teaching implementation of the two shifts is described below.

1.1 application of original experiment teaching implementation conditions

The original experiment applied to the seven-year-class 4 shifts is taught, and the experimental teaching implementation conditions are explained with respect to the preparation before class, the experimental process, the experimental phenomenon and reason, the time required by each group to complete the original experiment, the difficulty degree of the original experiment and the experimental conclusion.

1.1.1 preparation of the original experiment before class

1.1.1.1 preparation of teachers in the original experiment

The teacher should prepare the following before the experimental class:

first, the principles, steps and considerations of the experimental process are familiar and understood.

Preparing 8 pots of strong geraniums, and experimental equipment and reagents required by each group of experiments. The method mainly comprises the following steps: two 50ml triangular bottles, two 250ml small glass tanks, two 5000ml large wide-mouth transparent plastic bottles, a 200ml small beaker, a 500ml beaker, a large black box, a culture dish, a pair of dissecting scissors, a pair of tweezers, a box of matches, a glass rod, an asbestos wire, a tripod, an alcohol lamp, 30ml of 75% alcohol concentration, tap water, 10% sodium hydroxide solution by mass fraction, 60% vaseline, 50mol of 0.1mol/L iodine solution and the like.

And thirdly, grouping the students. As the number of people in one class is 40 and the number of people is more, the teacher needs to distribute the members of the group according to the comprehensive quality of the students and the wishes of the students, and each group comprises 5 people and is divided into 8 groups.

And fourthly, training the group leader of each experimental group. The main content of training is as follows: for the experiment, how to correctly use the sodium hydroxide solution, the alcohol solution and the alcohol lamp and how to operate the alcohol lamp are mainly responsible for assisting teachers to carry out experiment teaching.

1.1.1.2 student preparation of original experiment

The student needs to be prepared before the experimental class as follows:

firstly, each member in the group selects a group leader.

Secondly, the content of the experiment is pre-learned, the experiment steps are familiar, and sufficient preparation is made for the experiment operation.

1.1.2 Experimental procedures of the original experiment

The teacher instructs the students to participate in the experiment in the order of the groups. The experimental procedure was as follows:

and (4) dark processing. A basin of pelargonium is placed in a dark box in advance and dark treatment is carried out day and night, so that the pelargonium breathes to consume starch. Since the success or failure of the experiment depends on the dark processing time and the light intensity. The dark treatment time is too long, so that the normal physiological function of the geranium is influenced, and the photosynthesis is not vigorous; the dark treatment time is too short, and the starch is not completely consumed by the self-respiration action, so that the experimental result is influenced. Moderate illumination intensity is beneficial to photosynthesis, and the illumination intensity is too low, so that the photosynthesis is weak due to less light energy; over-strong light intensity, stomata close and plant wilting, resulting in weak photosynthesis. Therefore, before the experiment, teachers should pay attention to weather change conditions and attention to adjustment courses, and perform dark processing opportunities according to needs.

And sealing. Two branches which are approximately the same and are provided with blades are taken down from each group, the branches are respectively inserted into a small triangular flask filled with a proper amount of tap water, labels No. 1 and No. 2 are hung on the two branches respectively, the labels are also pasted on two small glass tanks and marked as an experimental group No. 1 and a control group No. 2, a proper amount of sodium hydroxide solution is added into the small glass tank No. 1, so that the sodium hydroxide absorbs carbon dioxide to become sodium carbonate and water, (at the moment, students are particularly reminded to pay attention to slow addition when adding the sodium hydroxide to prevent the sodium hydroxide from splashing to the skin, if the sodium hydroxide is splashed to the skin, water is firstly used for washing for at least 15min, the sodium hydroxide is wiped with cloth, then the sodium hydroxide is cleaned with 3% boric acid solution and is sent to a hospital to seek medical; then putting the No. 1 small triangular flask into the No. 1 small glass groove, and putting the No. 2 small triangular flask into the No. 2 small glass groove; then the two small glass grooves are respectively placed in a plastic bottle cap and covered with a transparent large plastic bottle, the plastic bottle cap is sealed, and vaseline is coated at the bottle mouth so as to prevent air leakage due to incompact sealing.

And illumination. And (3) placing the sealing device in the sun for illumination for about 2h, so as to enable the branches with the leaves to carry out photosynthesis.

And fourthly, decoloring. Decolorizing with 75% alcohol solution by heating over water to remove pigment from leaves. The decolorization principle is as follows: alcohol is a good organic solvent, can dissolve many inorganic and organic substances, so that it is commonly used to dissolve plant pigments and plant medicinal components. The leaves are heated by separating water from alcohol, other pigments are dissolved in the alcohol, and only lutein and carotene exist, so the leaves are yellow-white. The method comprises the following specific operations: opening a plastic bottle, respectively cutting off a leaf with a petiole from branches of the No. 1 small glass groove and the No. 2 small glass groove by using a dissecting scissors, respectively and correspondingly placing the two leaves into small beakers marked with the numbers 1 and 2 and containing alcohol, placing the small beakers into large beakers containing water, then placing the beakers on an asbestos net of an iron stand, heating the beakers by using an alcohol lamp, slightly pressing the petioles by using a glass rod to immerse the petioles in the alcohol, (particularly reminding students of paying attention to the use attention of the alcohol lamp at this moment), and clamping the petioles by using tweezers to take out the petioles when the petioles become yellow and white.

And fifthly, rinsing. Rinsing with clear water to wash off the alcohol solution on the leaves. Immediately, the yellow-white leaves were removed with tweezers and rinsed in a beaker of clear water for 4 s.

Sixthly, dyeing. Iodine solution is dripped for dyeing, so that the leaves can be dyed and are convenient to observe. Dyeing principle: the starch has free hydroxyl in each monosaccharide unit, so that intramolecular hydrogen bonds can be formed to form a spiral structure, iodine molecules in iodine solution are embedded into gaps of the spiral structure, and are connected with amylose by virtue of van der Waals force to form a compound with a large molecular weight, and the compound can uniformly absorb visible light except blue light, so that the starch presents blue. The method comprises the following specific operations: the petioles are clamped by tweezers to take out two rinsed leaves, and the two rinsed leaves are placed in a culture dish for 2 to 3 drops of iodine solution respectively, wherein the time is about 30 seconds.

And seventhly, rinsing for the second time. Rinsing with clear water to wash away iodine solution. The petioles were grasped with forceps and two iodine stained leaves were removed and placed in a beaker of clear water for rinsing for 4 seconds.

And (8) observing. The two leaves which are rinsed twice are taken out by clamping the petioles of the column with tweezers to observe the color.

1.1.3 Experimental phenomena and analysis of the original experiment

Experimental phenomena of the original experiment: as shown in table 1, the color of the No. 1 leaf of the A, E, H group was yellow-white, and the color of the No. 2 leaf was blue; B. the color of the leaves No. 1 and No. 2 of the group G is light green; c. The leaves No. 1 and 2 in the D group are all yellow-white.

TABLE 1 Experimental phenomena of the original experiment

Secondly, the original experimental phenomenon is caused by the following three reasons:

1) a, E, H group tag No. 1 leaves did not photosynthesize and did not produce starch, and tag No. 2 did photosynthesis and produced starch.

2) B, G group was interfered by chlorophyll and no experimental results were seen.

3) C, D group failed to see the experimental results for reasons: because the plant also breathes when carrying out photosynthesis, because the branch that takes off from a geranium and have the blade carries out the illumination experiment, leads to the normal growth function of branch to receive the influence, and photosynthesis is not flourishing or because the volume of carbon dioxide is not enough, and photosynthesis is not flourishing. The leaves of the F group 1 and the F group 2 are all subjected to photosynthesis, and air leakage is caused because the sealing device of the leaves of the F group 1 is uneven in sealing.

1.1.4 Each group required time to complete the original experiment

TABLE 2 time required for each group to complete the original experiment

The teacher makes statistics of the time to complete the original experiment for each group, and the results are shown in Table 2. 26.53H for group A, 26.58H for group B, 26.62H for group C, 26.55H for group D, 26.67H for group E, 26.68H for group F, 26.63H for group G, and 26.50H for group H.

1.1.5 original experiment difficulty

TABLE 3 difficulty of each set of evaluation experiments

The teacher exchanges with students and finds that the group A and the group H students consider that the experiment difficulty is moderate, and the group B, the group D and the group E students consider that the experiment is difficult; group C, group F and group G considered difficult experiments.

1.1.6 Experimental conclusions of the original experiment

As can be seen from Table 1, groups A, E and H were able to verify that carbon dioxide is an essential material for photosynthesis; group B, group C, group D, group F, and group G did not verify that carbon dioxide was the essential material for photosynthesis. As can be seen from Table 2, the student experiment duration is about 26.60 hours; as can be seen from Table 3, most students considered the difficulty or partial difficulty of the experiment, and only a few students considered the moderate difficulty of the experiment. In conclusion, the experimental phenomenon of the original experiment is not obvious, the time consumption is long, and the experimental difficulty is large.

1.2 Experimental teaching implementation conditions Using the invention

The experimental method applied to the seven-year grade 5 shifts is used for teaching, and experimental teaching implementation conditions are analyzed through preparation before class, experimental process, experimental phenomenon analysis, time required for completing the experiment of the invention in each group, experimental difficulty of the invention and experimental conclusion.

1.2.1 Pre-class preparation of experiments of the invention

1.2.1.1 preparation of teachers for the experiments of the invention

The teacher should prepare the following before the experimental class:

Preparing carbon dioxide (two small pieces of limestone are put in a dry test tube, sufficient diluted hydrochloric acid is added, gas capable of enabling clear lime water to become turbid is generated in the experimental process), purchasing 160g of algae and experimental equipment and reagents required by the preparation of experiments, wherein the steps comprise: an electronic balance, 4 small conical flasks of 50ml, 1 large beaker of 250ml, 1 conical flask of 100ml, 150ml of clear water and 5ml of litmus solution.

And exploring the division of the groups. The teacher distributes the members of the group according to the comprehensive quality of the students and the wishes of the students; each group had 5 persons, and the groups were divided into 8 groups of a, b, c, d, e, f, j, and h.

And fourthly, training the group leaders of each experimental group, particularly using the electronic balance and operating the electronic balance. Correct use of the electronic balance: leveling, preheating, weighing and finishing weighing.

1.2.1.2 Pre-class preparation of students for experiments of the invention

Firstly, each member in the group selects a group leader.

Second, the experiment content of the experiment course is pre-learned and sufficient preparation is made.

1.2.2 Experimental procedures for the experiments of the invention

Under the guidance of teachers, students participate in the experiment together, and the experiment steps are as follows:

marking a small conical flask. Each group is marked with 3 vials of the same size 1, 2, and 3. (the teacher at this point specifically emphasizes student safety, the erlenmeyer flask is a brittle glass that should be cleaned immediately upon breaking.)

② weighing algae. Each group of group length uses tweezers to clamp normal algae, places the algae on an electronic balance, respectively weighs 20g, places the algae in small conical bottles No. 1 and No. 2, and explains the using method of the electronic balance.

And thirdly, diluting the solution and subpackaging. 150ml of clear water is put into a big beaker, and 5ml of litmus solution is dripped into the big beaker to ensure that the solution in the beaker is purple; the purple litmus solution is divided into two parts, the two parts are packaged in conical bottles, one part is sealed by rubber plugs (50ml small conical bottles) and the other part is filled with carbon dioxide gas, the purple solution is changed into red solution (the carbon dioxide reacts with water to generate carbonic acid; the purple litmus solution shows red when meeting the carbonic acid; the green leaf plants absorb the carbon dioxide through photosynthesis to change the red litmus solution into purple), the ventilation is stopped, and then the rubber plugs are sealed (100ml conical bottles) for later use in the next experiment.

Fourthly, the litmus solution is injected. Filling a No. 1 small conical bottle with purple litmus solution without carbon dioxide; filling the small conical bottles No. 2 and No. 3 with a red litmus solution filled with carbon dioxide gas.

Illumination. The 3 small conical flasks were placed in a 25cm distance from a 100W fluorescent lamp and illuminated for 4 min.

Sixthly, observing and recording the experimental phenomenon.

1.2.3 Experimental phenomena and analysis of the experiments of the invention

Experimental phenomena: as shown in Table 4, the color of the solution in the small conical flasks 1 of group a, group b, group c, group d, group e, group f, group g and group h was purple, the color of the solution in the small conical flask 2 was changed from red to purple, and the color of the solution in the small conical flask 3 was red.

TABLE 4 Experimental phenomena of the invention experiment

Experimental analysis: no. 1 small conical bottles of the group a, the group b, the group c, the group d, the group e, the group f, the group g and the group h do not contain carbon dioxide, and algae can not carry out photosynthesis; the algae in the No. 2 small conical bottle is subjected to photosynthesis, and carbon dioxide is consumed; no. 3 small conical bottle has carbon dioxide but no algae, and can not carry out photosynthesis.

1.2.4 times per group for carrying out the experiments of the invention

TABLE 5 time required for completion of the experiments of the invention

The teacher makes statistics of the time taken for each group to complete the experiment of the present invention, and the results are shown in Table 5. 30min for group a, 32min for group b, 31min for group c, 32min for group d, 33min for group e, 29min for group f, 28min for group g, and 35min for group h.

1.2.5 ease of testing of the invention

TABLE 6 evaluation of the ease of testing of the invention for each group

The teacher exchanges with students and finds that the group d and group h students consider the experiment difficulty to be moderate, and the group a, group b, group c, group e, group f and group g students consider the experiment to be easy to complete.

1.2.6 Experimental conclusions of the invention experiments

From the above experimental phenomena, it can be concluded that all classmates can see the experimental phenomena, proving that carbon dioxide is a necessary raw material for photosynthesis. As can be seen from Table 5, the student experiment time is short, about 30 min; as can be seen from Table 4, most students consider the experiment to be easy to complete, and only a few students consider the experiment to be of moderate difficulty. The experiment of the invention has obvious experiment phenomenon, short time consumption and small experiment difficulty.

Compared with the original experiment, the experiment of the invention has the following advantages:

2.1 in terms of experimental operation

By comparing the difficulty and time of the experimental operation of the original experiment with the difficulty and time of the experimental operation of the experiment of the invention, the original experiment has great difficulty and takes long time for students to operate (table 2 and table 3); the experiment of the invention has small operation difficulty and less time consumption for students (tables 5 and 6).

2.2 in the experimental materials

Through comparing the experimental materials of the original experiment with the experimental materials of the invention, the experimental materials of the original experiment are pelargonium, and the experimental phenomenon of B, G two groups can show that pelargonium is difficult to decolorize, and has high alcohol consumption and high experimental risk. And most of the pelargonium roseum is maintained indoors, and can quickly wither when moved to strong light, the pelargonium roseum grows slowly, the quantity is limited, the petioles are fragile and easy to fall off, and the requirements of grouping experiments are difficult to meet. The experimental material algae of the invention has the advantages of easy obtaining and environmental protection: algae are common and can be collected throughout the year in the southeast of Qian; and the algae can be put back to nature again when used in the experiment, and is not like the leaves of the geranium which can only be discarded when being used once, so the experiment of the invention is more environment-friendly from the aspect of experimental materials.

2.3 in the experimental setup

By comparing the experimental apparatus of the original experiment with the experimental apparatus of the experiment of the present invention, the original experiment applied a dark treatment apparatus, a sealing apparatus, an alcohol lamp apparatus, a rinsing apparatus, and the like (fig. 1). The experiment of the present invention employed a weighing device, a simple carbon dioxide preparation device, a lighting device, etc. (fig. 2). It can be seen that the experimental apparatus used in the original experiment is more complex than the experimental apparatus used in the experiment of the present invention.

2.4 in terms of Experimental procedures

By comparing the experimental steps of the original experiment with the experimental steps of the experiment of the invention, the main experimental steps of the original experiment are dark treatment, sealing, illumination, decolorization, rinsing, dyeing, secondary rinsing and observation. The main experimental steps of the experiment of the invention are marking a small conical flask, weighing algae, diluting and subpackaging solution, injecting litmus solution, illuminating, observing and recording experimental phenomena. As can be seen, the original experiment is more complicated than the experimental procedure of the present invention.

2.5 in terms of experimental phenomena

Comparing the experimental phenomena of the original experiment with the experimental phenomena of the present invention, it can be seen that many students fail to see the experimental phenomena of the original experiment (table 1), while all students can see the experimental phenomena of the present invention with obvious experimental phenomena (table 4).

3.6 in terms of safety of experiment

Comparing the safety of the original experiment with the safety of the experiment of the invention, the sodium hydroxide solution of the reagent of the original experiment is found to be strong alkali, has corrosiveness and has potential safety hazard; and the decoloring is carried out by heating with alcohol in a water-proof way, so that a large amount of alcohol is needed, and certain danger is caused. The reagent of the experiment of the invention is litmus solution which is organic acid, has no corrosivity and has no great potential safety hazard.

3 conclusion

In conclusion, the experiment of the invention is superior to the original experiment in all aspects of experimental materials, experimental devices, experimental steps, experimental safety and the like, and the experiment of the invention is more suitable for experimental teaching.

Drawings

FIG. 1 is a schematic diagram of a conventional experimental model;

FIG. 2 is a schematic diagram of an experimental model of the present invention.

Detailed Description

The present invention is further illustrated by the following examples, which are not to be construed as limiting the invention.

Example 1. A plant photosynthesis teaching experiment method is carried out according to the following steps:

f. and observing and recording experimental phenomena.

Specifically, in the step a, the experimental container is a 50ml conical flask.

Specifically, in the step b, the weight of the algae put into each experimental container is 20 g.

Specifically, in the step c, the carbon dioxide gas is prepared by reacting limestone with sufficient diluted hydrochloric acid.

Specifically, in step e, the illumination specifically includes: the 3 labeled test containers were placed in a 25cm light for 4min from a 100W fluorescent lamp.

Claims

1. A plant photosynthesis teaching experiment method is characterized by comprising the following steps:

f. and observing and recording experimental phenomena.

2. A teaching and testing method for photosynthesis of plants according to claim 1, wherein in step a, the test container is a 50ml conical flask.

3. A teaching and testing method for photosynthesis of plants according to claim 1, wherein in step b, the weight of algae put in each test container is 20 g.

4. A teaching and testing method for plant photosynthesis according to claim 1, wherein in step c, the carbon dioxide gas is prepared by reacting limestone with a sufficient amount of dilute hydrochloric acid.

5. A teaching experiment method for plant photosynthesis according to claim 1, wherein in step e, the illumination is specifically: the 3 labeled test containers were placed in a 25cm light for 4min from a 100W fluorescent lamp.