Experimental method is the essence of the whole experimental design, and it is the key to do a good job in experimental design. Now some of the most common classical experimental methods related to middle school experiments are summarized as follows:

(1) Detection method of chemical substances:

① Starch-iodine solution

(2) Reducing sugar-Fehling reagent and Bancroft reagent.

③ CO2-Ca (OH) 2 solution or acid-base indicator.

④ Lactic acid-pH test paper

⑤ O2-ember rekindling

⑥ No O2-flame extinguished

⑦ protein-biuret reagent

⑧ Chromosome-gentian violet and magenta acetate solution

Pet-name ruby DNA-diphenylamine reagent

Attending fat-Sudan Ⅲ or Sudan Ⅳ dye solution

(2) Display method of experimental results:

① Photosynthetic rate-O2 release or CO2 absorption or starch production.

② Breathing rate-O2 absorption or CO2 release or starch reduction.

③ Atomic pathway-radioisotope tracer method

④ Cell fluid concentration-plasma wall separation

⑤ Cell death-plasma wall separation

⑥ Thyroid hormone action-animal oxygen consumption, development speed, etc.

⑦ Effect of growth hormone-growth rate (weight change, height change)

⑧ Insulin action-animal activity state

Pet-name ruby bacteria quantity-the number of colonies or the fading degree of methylene blue solution.

Attending Escherichia coli-eosin-methylene blue agar medium

(3) Control method of experimental conditions:

① Increase oxygen in water-pump air or blow air or put green plants.

(2) reduce oxygen in water-container sealing or oil film covering or using cold boiled water.

③ removing CO2——NaOH solution from the container.

(4) remove the original starch from the leaves-put it in a dark environment.

⑤ Removing chlorophyll from leaves-heating with alcohol in water.

⑥ Removing the interference of photosynthesis on respiration-shading plants.

⑦ How to get monochromatic light-prism dispersion or color film filtering?

⑧ Blood anticoagulation-adding sodium citrate.

Pet-name ruby mitochondrial extraction-cell homogenate centrifugation

Attending decalcification of bone-hydrochloric acid solution

⑾ Sterilization method-The key to microbial culture is sterilization. For different materials, the sterilization method is different: the culture medium is sterilized with high pressure steam; The inoculation ring is sterilized by flame burning; Wash your hands with soap, dry them and disinfect them with 75% alcohol; The whole inoculation process is carried out in the sterile area of the laboratory.

(4) Methods of controlling temperature in the experiment:

① Identification of reducing sugar: boiling and heating in water bath.

② Enzymatic reaction: keeping warm in water bath.

③ Dissolve chlorophyll in leaves with alcohol: alcohol should be heated in water.

④DNA identification: boiling and heating in water bath.

⑤ Cell and tissue culture and microbial culture: constant temperature culture.