学习了第七章《粒子与宇宙》后,我们知道组成物体的分子很小,肉眼是看不见的,那么我们如何通过身边的器材来估测下分子的直径呢?在这里,我们来学习下用油膜法来估测分子的直径.实验步骤和原理如下:
(1)实验的研究对象是油酸分子,我们在实验前可以通过注射器测量出每一滴油滴的体积为7.5×10﹣6cm3.
根据汉语提示完成句子(1)He ____ (坚持) that she was the perfect girl to play the lead role in the play. (2) What about going to the concert with me tonight? Sounds good. But I don't feel well. I prefer to stay at home ____ (代替) of staying out.(3)We are sure you will become famous____ (立即) if you successfully host the show.(4)Bill Gates and some others promised to ____ (奉献) much of their money to Charity.(5) Why was the young man arrested? He was charged of ____ (强行闯入) into the bank's computer systems and stealing important information.(6)Tom got along with all his neighbors ____ (除了) the man who looked strong. (7)Has the man ____ (证明) that he was at another place when the accident happened?(8)Was he out of ____ (呼吸) after running for a quarter around the playground?(9)The victim obviously put up a good fight against the ____ (冷酷的) murderer.
在测定反应速度的探究实验中,下列做法或说法正确的是( )
下列选项中字形完全正确的一项是( )