"I think you're going to make a big mess." That's how my 10-year-old answered the question, "What do you think is going to happen?" I had everything set up for this experiment and my boys were on full alert. While it was a little messy, it was also totally awesome. Here's how we poured water down a string and what you need to do it too. Supplies Pitcher Water String (we used a tightly woven yarn) Wide-mouthed glass or jar What to Do Fill the pitcher with water. A small pitcher will work best; our large pitcher was too heavy for my boys to pour slowly and steadily. Tie one end of the yarn around the pitcher's handle. Drape the string over the pitcher's spout and take the dangling end and hold it on the inside rim of your glass. Hold the pitcher at an angle and gently pour the water. You may drip some water at first so have a towel handy. IMPORTANT: the string must be touching the spout. A fuller pitcher means you won't have to tip it so drastically. Watch as water cascades along the string, clinging to it, until it reaches your glass. How It Works This is a great experiment to illustrate the principle of cohesion (particles of the same substance sticking together). Once the string is wet, the newly poured water wants to adhere to the water molecules already absorbed by the string.