What you need:
Water, glass bottle, plastic mesh or wire screen, rubber band, and toothpicks.
Cut a small square piece of the screen, place it on the mouth of the bottle and secure it with the rubber band. Fill it up completely with water through the mesh. Cover the mouth of the bottle and flip it, don't worry it won't spill. Now push the toothpicks through the screen and it still doesn't spill!
Cohesive properties of water cause it to form a bond in small openings of the screen, creating a “membrane” that essentially seals the mouth of the bottle. The outside air pressure is also greater than the pressure of the air pockets inside, holding the water up.
When the toothpick is pushed, the water wraps itself around the toothpick due to it’s cohesive property. Once the toothpick is through, the water releases it and floats up since it’s less dense than the water.