Improper use of the hottest glass instrument reduc

Improper use of glassware reduces its service life

some students are afraid of trouble and illegally use centrifugal test tubes to heat directly. Due to the uneven thickness of the bottom wall of the centrifugal test tube, it caused cracking. If the heating appliance that needs to be accurately weighed is not cooled after being dried out, it should be put into the dryer immediately. After the hot appliance with high temperature is put into the dryer, the air in the appliance will be heated and expanded, which may flush the cover away; Even if it can be covered, it is often difficult to open the cover because the air pressure inside the device will be lower than that outside the device after cooling. Some may crack the dryer; When moving the dryer, do not press the cover with the thumbs of both hands, but only the lower part, so that the dryer cover slides down and breaks, causing artificial instrument damage, etc

psychological disorder and carelessness of the experimenter are another reason for the damage of glass instruments. If teachers overemphasize the interests of improper experimental operation in daily teaching, students will be afraid and anxious when doing experiments, and timid in experiments

for example, when testing the purity of hydrogen, I was afraid to ignite hydrogen. Holding the test tube full of hydrogen, I didn't dare to approach the flame for a long time. When I loosened my finger and heard the explosion sound, the test tube also fell to the ground in panic. Some careless students will directly take the container that has just been heated, but out of instinctive self-protection, they throw away the instrument in their hands, causing the damage of the glassware. When measuring the pH value of the solution, the glass bulb of the glass electrode is very thin, and it will break when it accidentally touches the beaker or hard object. If Solvay cannot be in time: the high-performance polymer used for medical devices and equipment is equipped with a glass electrode, this acidimeter cannot be used, causing great losses and waste. Washing acid and alkali drops reduces the emission of aluminum and lead compounds in waste water and waste gas by 2 tons/year. When fixing the pipe, it did not look ahead and backward, resulting in the breakage of the titration pipe orifice; The acid burette is aged and broken due to the corrosion of the rubber band, which makes the piston fall off and break. When holding the instrument with an iron clamp, either the clamp is too loose to make the instrument fall off; Either the clamp is too tight and the instrument is broken

after the centrifuge rotates at high speed, the centrifuge tube is twisted blindly, causing the centrifuge tube to break, and even cutting the experimenter's hand. When holding the iodine measuring bottle from the balance room to the laboratory, he rushed, the note did not pinch the neck of the iodine fixing bottle, and accidentally broke the iodine measuring bottle on the ground

prevention and measures to enhance ideological awareness and enhance students' ideological awareness of caring for experimental instruments are important prerequisites for reducing the loss of glassware. Students' leading class is the most important. In the first experimental class hour, the experimental teacher must educate the students to take care of the instruments and equipment in combination with the laboratory rules, students' experimental rules, emergency measures for general injuries in the laboratory and the provisions on compensation for students' damaged instruments. Make students understand the importance of taking good care of the instrument, and let them really understand that the damage of the instrument will not only cause economic losses, but also lead to the failure of the experiment. However, if the refrigeration system of the selected experimental box is very small, some even endanger personal safety

take precautions in the laboratory where students do experiments, post typical pictures of instrument damage caused by various reasons, which are often encountered in ordinary times, together with brief text instructions, so that students can see the cause of instrument damage

recycling of waste glassware in the experiment. Slightly damaged glassware can be repaired and reused. For example, the test tube perforated at the bottom can be reused by closing the hole with fire. The test tube with damaged nozzle and the upper part of the scale line of the pipette can be cut off, and then melted on the flame. It can continue to have the advantages of stable operation, high reliability, simple protection, wide application range and so on. Cut off the branch pipe above the test tube, which can be used as an ordinary test tube, etc