1, be sure to keep the experimental table clean and tidy. All bottles containing chemicals should be labeled with names and concentrations, and placed on the experimental platform in a certain order.

2. Glass bottles containing chemical reagents must be clean and dry.

3. When using acid or other irritating chemicals, don't smell directly with your nose, so as not to irritate your eyes and nose. When diluting the strong acid, it is necessary to slowly pour the strong acid into the water and constantly stir it with a glass rod. You can't pour water into strong acid, otherwise it will explode and be very dangerous.

4, easy to absorb water vapor deliquescence or volatile chemical reagents, after bottling or use, to close the cork. Oxidizable chemicals should be put in colored bottles and stored in a cool place.

Extended data:

Comparing specimens is mainly to compare the similarities and differences of an organ of different plants. For example, to compare the seed morphology of dicotyledonous plants and monocotyledonous plants, it is necessary to collect mature fruits, such as rape, soybean, cucumber and tomato, remove the peel and dry the seeds, and also collect the fruits of wheat, rice and corn for comparison.

Compared with various forms of roots, we can collect cotton with straight roots, rice and wheat with fibrous roots, radishes with bulbous roots, carrots with conical roots, radishes with cylindrical roots, adventitious roots of tuber potatoes, corn and sugarcane, and parasitic roots of Cuscuta chinensis and Taxilli.

Comparing the stems of various shapes, we can collect peaches and Ficus carica with erect stems, morning glory and honeysuckle wrapped around the stems, strawberries with stolons, grapes with climbing stems, gourds, Parthenocissus tricuspidata, prickly hawthorn, Gleditsia sinensis, cactus with fleshy stems, epiphyllum, water chestnuts with bulbs, Chinese cabbage with bulbs, onions and garlic.