Take the caps of the bottles which are having two holes. Now take 4 straws and fix them on the caps using m-seal and cut them as done in the video so that the length of the shorter straws is same of the both caps and the length of the longer straws are different. Fill the bottles with water and close them using caps. Now empty them in container so that the water comes out from the longer straws first. Now see which one of them gets empty first.