What you need:
A tissue paper napkin, a glass, a tub, water
What to do:
1. Fill the tub with water Make sure there’s enough water so the glass can get completely submerged.
2. Roll your tissue paper into a ball and stuff it into the glass, right against the bottom.
3. Turn the glass upside down. Make sure the tissue doesn’t drop out!
4. Now, keep holding the glass upside down and immerse it into the water. The glass should not tilt to one side
5. Lower the glass until it is completely in the water
6. Pull the glass out again, still keeping it straight. Now, check on the tissue.
7. Try the experiment again and this time. let the glass tip over to one side after you’ve immersed it
What happens:
When you keep the glass straight, the tissue paper remains dry even though it has just been in the water. But when the glass has been tipped to one side, the tissue gets wet.
Why?
A glass that looks empty is never empty! There’s always air in it. When you lower the inverted glass into the water, air gets trapped inside it. Air is lighter than water, so it stays on top. Which means that the area near the bottom of the glass is like a pocket of air. As long as the air’s there, the tissue stays dry.
When you tip the glass to one side in the water, do you see bubbles? That’s air escaping from the glass. Once the air’s gone, there is nothing to save the tissue from the water and it gets wet.
Picture Credit : Google
