This experiment was really quick but was just as fun! I started off by grabbing one of my plastic cups and filling it to the top with water! Then my mom heroically found index cards that will completely cover the top of the cup.
Here is the daring part. Picking it up, I held it over a large bowl and flipped the whole thing upside down. Then I removed my hand!
WOW!! It stayed in place. It dripped a little bit but no splash. I did the experiment again (who wouldn’t?) and it lasted about seventeen seconds. Magic? No, SCIENCE!
How does it do that? It is all about air pressure. When I flip the cup over, the pressure outside of the cup and inside of the cup is the same. But the cup released some water. That resulted in the same amount of air at the bottom (or top) of the cup but it has to occupy more volume since some water escaped. Thus, the pressure decreased just a little inside of the cup. Now the pressure outside of the cup is greater than the pressure inside. That pressure is pushing up on the card, keeping it in place. Ha ha!! That is so cool! I just LOVE doing the experiment but finding out why it does what it did can be just as fun!
Now it is time to eat lunch and then start the last experiment for the day!
