Pour in a glass of carbonated water. Take a small button and place it in a glass. The button will be at the bottom. Immediately or a little later, move your hand above the Cup and say: "Button, to me." Button slowly rises. Again, run your hand over the glass and say, "Button down". She obediently falls.
When they will be pretty much they will raise button. Then the bubbles will disappear and the button again due to its own weight will go down. This movement - up and down - lasts as long as carbon dioxide is released. Calculate the time, how long to wait before you say the button "up" or "down".
Why is this happening? When the button is at the bottom of the glass, the bubbles of carbon dioxide going around it.