题干

某研究性学习小组为研究热在固体间是如何传递的,做了如下实验:

⑴把一块长条状铁片,放入水中浸湿。

⑵在铁片的一端用酒精灯加热(如图),观察发生的现象。

请回答:

①把铁片放入水中浸湿的目的是:____

②如果热从温度高的地方传向温度低的地方,则热从____端传向____端。

③如果我们在A处加热,则会观察到____

上一题 下一题 0.0难度 选择题 更新时间:2018-12-24 04:40:25

答案(点此获取答案解析)

使铁片粘有水分,A,B,从A端至B端水先后蒸发

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    Skateboarding is an action sport which includes riding and performing tricks using a skateboard, as well as an activity for fun, an art form, an entertainment industry job, and a method of transportation. In 2016, it was announced that skateboarding will be represented at the 2020 Summer Olympics in Tokyo, Japan.

    There are various theories about the origins of Skateboarding, but it is generally held that the sport began in the 1940s on the west coast of the USA when metal wheels were attached to a narrow wooden board. In the 1950s, plastic replaced metal as the material of choice for the wheels, and the first "Roller Surfboard" become commercially available, which in turn developed into the skateboard that we know today. The sport was a big hit with the younger generation and grew in global popularity in the 1980s and 1990s. Since the late 1990s, skateboarding has become an important part of street culture.

    However, skateboarding has raised heated discussions in areas where the activity, although legal (合法的), has damaged stone works, steps, benches, and parks. Certain cities oppose the building of skate parks in their neighborhoods, for fear of increased crime (犯罪) and drugs in the area. The disagreement between the old image of skateboarding and a newer one is quite obvious: magazines such as Thrasher describe skateboarding as dirty, and still firmly tied to punk (朋克), while other publications, Transworld Skateboarding as an example, paint a more different and controlled picture of skateboarding. As more professional skaters use hip hop, or hard rock music in their videos, many urban youths, hip-hop fans and hard rock fans are also drawn to skateboarding, weakening the sport's punk image. Besides, group spirit influences the members of this community. In presentations of skateboarding, the evidence of crime is absent, and no attempt is made to tie extreme sports to any kind of illegal activity.

    The good news is that efforts have been made to improve recognition of the cultural heritage as well as positive effects of skateboarding in cities. By raising £790,000, the Long Live Southbank initiative managed to stop the destruction of a forty years old spot in London due to urban planning, a rescuing operation whose effect extends beyond skateboarding. The presence of skateboarders on this public space keeps the area under nearly constant watch and drives homeless people away, increasing the feeling of safety in the area. The activity attracts artists such as photographers and film makers, as well as a significant number of tourists, which in turn drives economic activity in the neighborhood.