取透明塑料袋一个,装入适量的菠菜或其它植物的鲜叶片,在扎口前插入一根长约10厘米左右的细玻璃管,扎紧袋口。将玻管的另一端插入盛有澄清石灰水的小烧杯内,挤压口袋,可见石灰水没有什么显著变化。用血压计打气球或洗耳球对准玻璃管向袋内吹气,或重新打开袋口灌入空气,然后装入黑色口袋内,或其它黑暗处。约10—15分钟(这要依气温和叶片多少 Take a transparent plastic bag, put in the right amount of spinach or other fresh leaves of plants, insert a thin glass tube about 10 cm in front of the tie, tie tight pocket. Insert the other end of the tube into a small beaker of clear lime water and squeeze the pockets to see that there is no significant change in lime water. Use a sphygmomanometer to inflate the bag by placing balloons or earbuds in the glass tube, or re-opening the bag to fill the air, and then into the black pocket, or other dark place. About 10-15 minutes (depending on temperature and number of leaves)