在对蜡烛及其燃烧进行了探究以后,请你填写下列空格: (1)哪些是需要燃烧才能观察

题型:实验题

问题:

在对蜡烛及其燃烧进行了探究以后,请你填写下列空格:

(1)哪些是需要燃烧才能观察到的现象_________(填序号)  

①自顶端起约1cm以内的烛体是温的.柔软且易塑型;

②原料是半透明.微臭.无味白色固体;

③蜡烛顶端.烛心底部周围有无色液体,呈凹状;

④一白色烛心贯穿中轴,并延长至蜡烛顶1cm;

⑤形状圆柱形,顶部为圆锥形尖出;

⑥烛心周围和烛焰上端呈明亮的黄色;

⑦吹熄后,能看见烛心周围有白烟上升,并慢慢消失;

⑧质软,可用指甲刮出痕迹;

⑨若风吹至蜡烛一边,另一边凹形顶端的蜡烛将熔成液体并沿烛体落下;

⑩受空气流的影响,火焰会闪动,且生出黑烟。

(2)取一支蜡烛,用小刀切下一小块,把它放入水中,蜡烛会________。 结论:石蜡的密度比水________。

(3)再将一只干燥的烧杯罩在蜡烛火焰上方,烧杯内壁出现________,片刻后取下烧杯,迅速向烧杯内倒入少量澄清的石灰水,振荡后发现________。结论:蜡烛燃烧以后的生成物有________。

(4)如图所示,将桌面上两支燃着的且高低不同的蜡烛用一大烧杯罩住,最先熄灭的是_________,其原因是___________。 

考点:蜡烛燃烧
题型:实验题

胆囊炎穿孔的典型声像图表现是()

A.胆囊肿大,轮廓模糊

B.胆囊壁弥漫增厚,形成"双边影"表现

C.轮廓模糊,胆囊壁可见强光团

D.胆囊壁局部缺损,胆囊周围局限积液

E.探头压迫胆囊区疼痛明显

题型:实验题

麦考莱

题型:实验题

下列哪一事例可以说明大气压的存在(  )

A.用吸管可吸牛奶

B.两个气球相挤压都变形

C.火烟高升

D.水往低处流

题型:实验题

B


It keeps your insides from falling out. It helps you warm up when you are cold, and it can cool you off when you are hot. It lets you feel things by touch.
What is this Your skin, of course! What does your skin ask for in return for all the wonderful things it does Just a little care! So let’s learn how to take good care of our skin.
Like the heart and stomach, your skin is an organ(器官). In fact, it is the largest organ in your body. Unless there’s a problem, you may not think about your skin very much. But skin has an important job to do.
Your skin is protecting you. Your skin keeps you from getting sick. When you take care of your skin, you are helping your skin do its job. Taking care of your skin today will help you have no problems in the future.
Clean skin is happy skin! One simple way to take care of your skin is to keep it clean. Keeping your hands clean is very important. When washing your hands, use warm water. Wet your hands, and then use soap. You should wash your hands carefully everywhere.
You’ll also want to use warm water, but not too hot, when you take a bath. Use soap to clean your body. Don’t forget under your arms and behind your ears! Your face needs attention, too. It’s a good idea to wash your face once or twice a day with warm water.

We can infer(推断)from Paragraph 3 that ______.

A.people don’t often care much about their skin

B.skin is an organ

C.there would be nothing wrong with your skin

D.skin is not important at all

题型:实验题

国家创新体系建立所需要的几个方面()。

A.技术创新体系

B.知识创新体系

C.科技中介服务体系

D.创新的政策体系

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