Hurricane in a bottle
2 x 2l bottles
Water
Duct tape or electrical tape
Oil and Dye (optional)
What to do:
1.
Fill one of the bottles two thirds full of water
2.
Put the empty one on top of the bottle with
water in it and tape the necks together securely
3.
Turn the bottles upside down and watch what
happens.
4.
Repeat again but this time swirl the water
How does it work?
It’s all about the spin.
It is the same principle that helps a hurricane force winds to speed up.
The reason why the 1st attempt took longer than
the second is because the space in the upper bottle needs to be filled with air
to replace the space that was taken up by the water else it would leave behind
a vacuum. The air from the bottom bottle
rises through the narrow neck to do this.
However, while the water is flowing downwards and the air is pushing
upwards the air bubbles slows the water flow down.
In the 2nd attempt however, where the bottles are
swirled, as the water is goes through the necks of the bottles it is forced to
go in to tighter and tighter circles – the same principle applies to
pirouetting ice skaters; they rotate quicker when their arms are pulled into
their bodies – these tight circles make a gap in the centre of the necks and allow
air to flow freely through which allows the water to flow freely into the
bottle below as there are no obstructions.
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