The behavior of water and air can depend not only on factors like pressure and weight, but also motion. This nifty demonstration recycles used plastic bottles to show basic physics concepts in an exciting and interesting way.
Here's what you'll need:
Two plastic water bottles
One washer (that fits the bottle-lids snugly)
Step 1: Start Recyling!
Step 2: Half-Full
Step 3: Already Empty
Step 4: Get Crafty
Step 5: Swirl of Science
Flip the filled bottle so it is on top, give the setup a good swirl, and watch the water whirl!
It may take a few tries to get the hang of how much to swirl the water; don't be discouraged.
Step 6: Learning Why
The reason this drains faster is because, if you look close, you can see that throughout the whole process there is a hole where the air can flow up, surrounded by draining water. This makes for a much faster drainage than the traditional glug-glug of pouring from bottles. The glug-glug comes from the water and air having to both use the same passage; when the air is rising, the water ceases flowing and vice versa. This makes for slower drainage than the continuous vortex.