The whirl gangs

One bottle is filled with water. If you turn over the filled bottle at the top, there is a poor flow of water to the bottle below, or no flow at all. Why is that?

A thin film of surface tension is created in between the holes in the bottles. It is also caused by low pressure forming in the bottle containing water. If there is a lot of water in the top bottle, the surface tension breaks and the water starts to run into the bottle underneath. The pressure increases in the bottle below, and air bubbles are pushed up into the bottle at the top.

When the bottles are rotated, a whirl is created. The air passes through the whirl and the low pressure disappears so the water can run out with help from its own weight. The weight drags the water downwards inwards. The speed at which the water rotates and the sides of the bottle create constant movement which increases the water’s speed as the bottle gets narrower.

Where can you see this?

Different whirls can occur in many parts of nature, both in the air and in the water. Tornadoes, whirlpools and weather systems are examples of whirls

Sustainable development

When the temperature in our atmosphere and seawater rises, this creates larger conditions for building devastating tropical hurricanes. Tropical hurricanes create energy with help from high humidity that condenses in the atmosphere. They are set in motion by warm air currents from the side.