Put the lid on tight and swirl the jar in a circular motion several times and then stop and look inside the jar. Be careful to make sure the outside of the jar is dry and hold onto the jar tightly. You should see what looks like a tornado. The tornado will slowly dissipate as it moves upward towards the top of the jar. A tornado is a violently rotating column of air in touch with the ground and is created by its parent thunderstorm.
Most tornadoes come from a type of thunderstorm called a supercell.
A supercell is a rotating thunderstorm which can produce one or more tornadoes. If conditions are favorable for the development of thunderstorms which could produce tornadoes, the National Weather Service will issue a Tornado Watch. When a Tornado Watch is issued, you should know where your place of safety is in case a Tornado Warning is issued. If a Tornado Warning is issued, it means a tornado has been detected by radar or has been spotted. You should move to a place of safety as quickly and calmly as possible.