3 sentences

1. 这次科学实验失败了。

   zhè cì kē​xué shí​yàn shī​bài le.

   The scientific experiment failed.

   Source: Dong Chinese Dictionary

2. 宇航员正在空间站进行科学实验。

   yǔ​háng​yuán zhèng​zài kōng​jiān​zhàn jìn​xíng kē​xué shí​yàn.

   Astronauts are conducting scientific experiments on the space station.

   Source: Dong Chinese Dictionary

3. 老师正在指导学生们如何进行科学实验。

   lǎo​shī zhèng​zài zhǐ​dǎo xué​sheng men rú​hé jìn​xíng kē​xué shí​yàn.

   The teacher is guiding the students on how to conduct scientific experiments.

   Source: Dong Chinese Dictionary