Materials required:– a small mouthed bottle and water.

Take about 1/4 full of water in a bottle. Hold the mouth of the bottle to your mouth and blow hard into it. After blowing  hard enough close the mouth of the bottle with your thumb. Slant the bottle and now the water is touching your thumb. Gently release the pressure of your thumb. See how the water from the bottle jerks out like a fountain. Repeat this many times and enjoy this fun. Care should be taken and the air inside the bottle should not leak. Do not blow and close the bottle after sometime. Compressed air would have been escaped. So you must close the mouth of the bottle as you are still blowing into it.

Why does the bottle spout out? The air blown into the bottle is compressed air. When you tilt the bottle the compressed air pushes the water out. If you do this with a bottle of water without blowing into it, the water will only drip out in jerks.