This experiment seemed really simple and easy but it was a little tricker than I thought. We initially used a large mason jar which was just too big and heavy to swirl around fast enough to get a good tornado going. Also, my son initially shook it up which the directions said was fine but that just made the water cloudy and hard to see the tornado. We switched to a smaller jar, added some food coloring and let it settle a minute and then we were able to swirl it and get a good tornado, which my son loved. I would definitely suggest a smaller glass jar or preferably a plastic container. We also shined a light under and behind it which made it easier to see as well. Was fun but was a little frustrating to start off.