You will need:
- 2 glass bottles (plastic bottle will also do, but
they should not have
bendable walls) - Sink or a place outdoors
- Stopwatch
Race your friends with this watery experiment to figure out the fastest way to empty a bottle.
INSTRUCTIONS
- Ask your friends what they think is the fastest way to empty a water bottle.
- Once you have a few ideas and have tried out different ways to empty the bottle, try emptying one bottle by turning it over and holding it erect upside down.
- Holding the other bottle also upside down, gently swish it till you create a whirlpool inside the bottle. Keep swishing the bottle till all the water is out.
- Which bottle emptied faster? And why?
RESULT
The bottle which was swished around will definitely empty faster than the bottle that was held in a fixed position upside down. This is because when the water leaves the bottle, it does so in great speed. However, the emptying water is now making place for air. But for the air to go into the bottle, it has to push through the water and hence slows the speed at which the water leaves the bottle. However, by swishing the bottle, you are creating a vortex of sorts, which leaves a passage in the centre of the water for the air to go through, thus resulting in the air entering the bottle without hampering the speed at which the water leaves the bottle.
