So this activity could not be any easier or more fun! My kids did this for so long and kept coming back to it. Let me preface this with the fact that we have done all sorts of activities that include blowing through a straw as opposed to sucking through it. We have blown cotton balls, blown paint around paper (water it down a little first), blown the wrappers off the straw at restaurants, just to name a few. So they knew what I meant when I told them to blow through the straw. If you try this with your kiddos, practice blowing first, please. Otherwise, they will most likely suck up a horrible mouthful of Bubble Juice!! All you need is a bowl, a couple squirts of liquid dish soap and some straws. I placed a towel under us because the tile gets slippery with the soap. Then we just blew, blew, blew! We had a contest to see who could make their bubbles the biggest. It was such fun. (If your bubbles are popping to soon, just add more soap). Bubbles are the perfect example of surface tension...a great science activity. Bubbles are actually thin balls of liquid with air trapped in the center.