You will need
- Scissors, cardboard (thin) or thick paper, ruler, 1 Cup, 1 marker, bowl of glass or plastic, the water in the jug.
To conduct this experiment (or focus) need to be prepared. To do this, cut out with scissors from a sheet of cardboard square. It needs the size to be larger than the diameter of the glass and act beyond the edges of 3 cm Write marker to cut a piece of cardboard the inscription "do Not shake!" This should be remembered by you and your audience. Put on the table a container of glass or plastic, empty glass, the water in the jug, place the prepared cardboard.
Fill the glass with water, right to the edge. Take the cardboard in the arm with the lettering facing up and place it on the edge of the glass. Hand must be clean, not sticky to the cardboard to it is not stuck at the crucial moment. With a quick movement, invert the glass, holding in the palm of the cardboard. Do it over the bowl. Place the cardboard carefully in the bowl, remove the hand too cautiously. You and your audience will see that water without spilling a drop, and it continues to be in the glass.
The same experience can be produced with different amount of water in the glass, different materials hold water in it like a regular album sheet. You can also not put the cardboard on the bowl and take your hand from the sheet, holding the top of the beaker with the other hand. The result is always the same, and the water will not spill.
This experiment has a scientific explanation based on the physical properties of substances: the water doesn't spill outside of the cardboard, because between it and the cardboard it creates air pressure, which acts on the paper. Also the role played by the scientific fact that molecules on the surface of any liquid in contact together and creates an invisible film. In this case, the film is formed on the surface of the water when it borders paper. In fact, water in this case is almost "glued" to a sheet of cardboard.