Cool Science Magic Trick
- Ball or mason jar (a glass jar with lid and a screw band to hold the lid in place like in the picture on the right)
- Wire screen
- Playing card
- 1 cup of water
- Adult supervision
- With an adult’s help, cut the wire screen or door mesh to the size of the lid.
- Place the mesh over the bottle mouth. Secure it with the screw band.
- Without letting your audience see the mesh, fill the jar through the mesh, making them think the jar is wide open.
- Place the playing card and cover the screen completely. Now turn the jar upside down with the playing card pressed tightly against the screen.
- Once upside down, slowly remove your hand to show the card sticks to the jar! The card is preventing the water from falling!!!
- Now slowly remove the playing card. Magically, the water does not come pouring out through the screen!!!!
- While still holding the bottle upside down, tip the jar to one side, and pour the water out.
How Does It Work?
When you submerge a screen into water and then pull it out, you will see that water fills the holes of the screen. The force holding the water to the screen is called adhesion. The film of water is held tight due to a force called cohesion. Cohesion is the attraction between molecules of the same type, while adhesion is the attraction between molecules of different types. The cohesion force creates surface tension, which is why water drops are round. The surface tension in our mesh is so strong, that it prevents air from going into the jar to replace the water as they pour out. As a result, water stays in the upside-down jar even after the card has been removed. When you tip the bottle, it breaks the surface tension and the water comes out.