How does it work?
When the water creates a seal with card when turned upside down, the air pressure from outside becomes stronger than the pressure inside the cup, allowing the card to be pushed up & stuck to the bottom of the cup.
If there is a small gap between the card and the cup, air pressure will enter the cup causing the card to fall down!
If there is a small gap between the card and the cup, air pressure will enter the cup causing the card to fall down!
How does it work?
There’s a small air bubble inside the ketchup packet which keeps the ketchup from sinking. When you squeeze the bottle, you put pressure on the packet, causing the bubble to get smaller and the packet to become more dense (or heavier). As the packet becomes more dense than the water around it, it will sink!
Release the pressure and the bubble expands causing the packet to float back up again.
Release the pressure and the bubble expands causing the packet to float back up again.
