Materials Required A transparent straw A glass of water A blade How to do it Take the straw and make a small cut in the middle of the straw. Bend the straw to 90 degree. Now, place one end of the straw in the glass of water and the other end in mouth of your kid. Ask the kid to blow the air through the straw and ask her to observe what happens. Few water will rise up in the vertical straw. Explanation Moving air exerts less sideways pressure than still or less turbulent air around it. The moving air at the upper end of the straw(which is kept in the mouth) reduced the pressure in the vertical straw. As the atmospheric pressure on the surface of water was greater than the pressure in the straw, few amount of water was forced to rise up into the straw.
How to do it
Explanation