题干

小明用细铁丝、棉线、肥皂水等探究分子之间相互作用力,过程和方法如图用细铁丝做成一个圈,中间松松地系上一根小细棉线,如图甲所示.

(2)在肥皂水中浸一浸使肥皂水留在上面,如图乙所示.

(3)用手指轻轻地碰一下棉线一边的肥皂膜,(如图丙所示)猜一猜会出现什么现象, ____.通过这个实验你可以得到什么结论: ____

(4)小明还做了如图丁所示实验,上瓶内装有空气,下瓶内装有红棕色的二氧化氮气体(密度比空气大),将上下两瓶间的玻璃片抽掉,过一段时间后,两瓶气体混合在一起,颜色变均匀.这个现象说明 ____

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答案(点此获取答案解析)

左侧肥皂膜破裂,棉线被拉向另一边,分子间有相互作用的引力,分子在不停地做无规则运动.

同类题1

阅读理解

    Palema Malhotra and her husband Anil Malhotra have spent the last 25 years buying the waste agricultural land and reforesting it, to return the land to a bio – diverse rainforest for elephants, birds and other creatures.

    The couple owns 300 acres of land in Brahmagiri, India. They have spotted more than 300 kinds of birds as well as many rare and threatened animal species. But, this was not the scene in 1991 when Anil and Pamela came to this part of the country. “When I came here, it was a wasteland. The owner wanted to sell because he couldn't grow coffee or anything else,” says Anil who worked in the real estate(房地产)and restaurant business in the US before moving to India. “For me and Pamela, this was what we were looking for all our life.”

    The couple had a love for nature from their childhood. When the Malhotras came to India, the pollution horrified them. “That was when we decided to do something to reclaim(开垦)the forest in India,” says Anil. “We were not looking for money. Early on, we realized that shortage of fresh water will be a concern for India and the rest of the world. Acquisition, protection and reclamation of forested lands and wildlife habitat, where vital water sources have their origin, is the only way to save ourselves,” explains Anil.

    They sold what they owned in America, bought the first 55 acres and began to grow a forest. Soon they bought the land nearby as well. “Many of the farmers considered their holdings 'wasteland' as very little grew on it and were happy to get money,” says Anil.

    Hunting and poaching(偷猎)was a challenge and often the locals did not understand what this couple was doing, so it required a lot of talking to create awareness. They worked with the forest department to set up camera traps and keep poachers away. “There are times I have fought with poachers,” says Pamela.

同类题4

创新是引领科技发展的第一动力,******强调:“科技是国家强盛之基,创新是民族进步之魂”。阅读材料,回答问题。

材料一:作为中部地区的区域中心城市,武汉的经济发展了,可水环境却承受着极大的压力。为此,2015年1月,武汉市政府印发了《武汉市中心城区排涝、治污、供水两年决战行动计划》,计划用2至3年实践,实施149个项目,投资140亿元,全力推进雨污水管网混错接改造和社区、高校、企事业单位内部雨污分流改造工作。为贯彻落实这一决策,武汉市各级政府、广大干部群众积极行动起来,一个全社会参与美丽江城建设的良好氛围正在逐步形成。

材料二:因为利用了最新的科技成果,转车方便、快捷、支付简单。加上惬意推广的补贴,优惠的价格吸引不少市民选择专车服务。目前,出租车行业主要依赖于政府限制运营数量,实施保护价格的措施来进行运营和管理。专车服务与出租车行业产生了强烈的利益冲突,因此在许多国家的扩张都受到了激烈反对。政府出于经济稳定和就业保障的目的,保护出租车行业的做法受到社会质疑,这种做法会损害消费者权益,容易滋生腐败现象。

材料三:由于转车“跑得太快”,法规“跟不上”,结果就出现了一个灰色地带,使政府对交通客运行业的管理变得困难。但转车服务的新模式,又能满足市场上高品质、多样化和差异化的出行需求。对此现状,中国交通运输部认为,不能对专车“一棍子打死”,要按照以人为本、鼓励创新、趋利避害、规范管理的原则进行管理。