排序方式： 共有10条查询结果，搜索用时 324 毫秒
1
1.
段慧芝 《小学生导刊(高年级)》2011,(Z2)
天刚蒙蒙亮,整条小巷便忙碌起来。各个商店纷纷开门了。古巷两旁的商店里摆满银器、蜡染、花环、玩具,还有血粑鸭、糯米酸辣子、酸汤鱼、腊肉……那些现做现卖的姜糖作坊,把整个巷子弄得空气流香,叫人馋得实在难以忍受。咔吱——咬上一口新出炉的姜糖,闭上眼睛,任凭香、辣、脆、甜在嘴里回味…… 相似文献
2.
点火,上升,面带微笑地招手……还记得《环游地球八十天》的主角们是如何完成那艰巨而美妙的旅程的吗?可别小瞧了这些圆圆胖胖的热气球,它们居然连翅膀都没有,它们是怎么飞起来的呢? 相似文献
3.
4.
5.
Indoor environment separated with down.feed air curtain was numerically simulated and experimentally researched.Indoor airflow and temperature fields separated with air curtain were numerically simulated.Resuits show that both polluted airflow and thermal air current can be separated with a down.feed air curtain to prevent contaminants from spreading in the room space.In a test chamber.the smoke of burning Tibetan incense served as the source of contaminants.and the probe test shows that 1.0 pm is the prevailing diameter of the smoke particles.During the release of the smoke.the particle concentration of the indoor air was tested with a laser particle counter at the points of three different heights from the floor when the air curtain was running or not.Experimental results show that the higher the test point is located,the lower the particle concentration is,implying that the separating or isolating eflfect decreases as the air velocity of the curtain reduces along with the height descends.According to both simulation and experimental results.down.feed air curtain can separate indoor environment effectively when the supply air velocity of air curtain is not less than 3 m/s.In order to strengthen separation effect,it is suggested that the supply air velocity be speeded up to 5 m/s. 相似文献
6.
7.
8.
一、问题的提出"从海带中提取碘"是高中化学实验,做好该实验对元素化学的教学,以及培养学生运用所学知识与实验技能探究科学有着重要意义。按教材进行实验,实验时间长(整个实验由原来的1.5 h[1]减少至40 min),实验现象不明显,甚至检验不到碘的存在;对"从海带中提取碘"进行研究的人也不少[1-4],但有的所用仪器普通高 相似文献
9.
《学生之友(初中版)》2009,(3):2-2
把香烟打个结把有颜色的水倒入一只四角形瓶子里,然后用软木塞塞紧。软木塞上穿一个孔,插入一根吸管进去,一直插到瓶中的液体里。用胶条密封瓶口。当你用手握住瓶子时,吸管中的水就会上升。 相似文献
10.
正科学是一门以实验为基础的学科,是以培养科学素养为宗旨的科学启蒙课程。它着眼于学生科学素养的逐步形成,改变学生被动学习的方式,培养学生的创新精神和实践能力,致力于学生科学素养的形成与发展。那么,如何提高实验课的效率呢?一、精心准备实验材料材料的选择应该根据实际情况,因地制宜、贴近生活,选择的材料最好是随手可得的、随处可见的,和学生的现实生活有着紧密联系的。实验材料选择应科学、搭配精当,学生操作起来得心应手,观察方 相似文献
1