Stand the bottles upright, with the empty bottle remaining underneath. Questions Answer the following questions in the spaces provided. The water inside the upper bottle swirls, forming a funnel shape as it pours into the lower bottle. You have probably seen this happen when you let water out of a bath. The swirling air is then tilted upwards to form the tornado.
Air flows into the tornado through the bottom and out through the top.
Tornadoes are also called twisters. They range in size from a few metres across to about a kilometre wide. Extension Activity Investigate whether the direction of spinning affects the rate at which water flows from the top bottle to the bottom one. During the 1960's, a thunderstorm and a rapidly moving cold front produced a tornado in Sydney. It was about 600 metres high and 50 metres wide.