Why do cyclones spin clockwise in the southern hemisphere

Weather forecasters use the Coriolis effect as part of their calculations to work out how air moves from areas of high pressure to low pressure.

In the Northern Hemisphere it deflects to the right and moves into the low pressure zone counter-clockwise," explains McBride. Winds blowing slowly won't be deflected as much as strong winds. Winds at higher latitudes will be deflected more than winds blowing at the same speed, closer to the equator. The Coriolis effect is zero at the equator, so you don't get cyclones at all — you have to be at least 5 degrees north or south of the equator for a cyclone to form, says McBride.

But the equator is not wind-free. McBride says winds still travel from areas of high pressure to low pressure. Without a Coriolis effect, local conditions play a major role. These can include mountains, sea breezes, thunderstorms and monsoons. Large scale weather systems can also force winds across the equator from one hemisphere to the other.

The Coriolis effect only really works over large distances, not on the small scale of a toilet or sink. Horizontal movements are referred to as currents, while vertical changes are called upwellings or downwellings. Explore how ocean currents are interconnected with other systems with these resources. Hurricanes are tropical storms that form in the Atlantic Ocean with wind speeds of at least kilometers 74 miles per hour.

Hurricanes have three main parts, the calm eye in the center, the eyewall where the winds and rains are the strongest, and the rain bands which spin out from the center and give the storm its size. Meteorologists use the Saffir-Simpson Hurricane Wind Scale to classify hurricanes into categories one to five. Categories three to five are considered a major storm. A category five hurricane has wind speeds that exceed kilometers miles per hour. Coastal areas are often most heavily impacted by the damaging winds, rains, and storm surges as the storm collides with or brushes land.

Use this curated collection of resources to teach your classroom about hurricanes. Weather is the state of the atmosphere, including temperature, atmospheric pressure, wind, humidity, precipitation, and cloud cover. It differs from climate, which is all weather conditions for a particular location averaged over about 30 years. Weather is influenced by latitude, altitude, and local and regional geography.

It impacts the way people dress each day and the types of structures built. Explore weather and its impacts with this curated collection of classroom resources. An abiotic factor is a non-living part of an ecosystem that shapes its environment. In a terrestrial ecosystem, examples might include temperature, light, and water. In a marine ecosystem, abiotic factors would include salinity and ocean currents. Abiotic and biotic factors work together to create a unique ecosystem.

Learn more about abiotic factors with this curated resource collection. Catastrophic weather events include hurricanes, tornadoes, blizzards, and droughts, among others. As these massively destructive and costly events become more frequent, scientific evidence points to climate change as a leading cause. While they can often be predicted, the loss of life and property take an emotional and economic toll on the community impacted. Explore these resources to teach your students about catastrophic weather events and how they impact every part of the world.

The weather you encounter day to day depends on where you live. Places around the Equator experience warm weather all year round, but experience alternate periods of rainy and dry seasons.

Places near lakes may experience more snow in the winter, whereas places on continental plains may be more prone to hail, thunderstorms, and tornados in the summer. Learn more about regional climates with this curated resource collection. Rotation describes the circular motion of an object around its center. There are different ways things can rotate.

Wind is the movement of air caused by the uneven heating of the Earth by the sun. Join our community of educators and receive the latest information on National Geographic's resources for you and your students. Skip to content.

The reason is something called the Coriolis effect, or Coriolis force, named for the French mathematician Gaspard-Gustave de Coriolis, who published work on the effect in the 19th century.

It works this way: Like a record on a turntable, the earth spins at a different speed at the equator than it does at the North Pole. The same is true of anything that spins or rotates — the outside edge of something in this case, the equator always spins faster than the inside edge.

If you placed a marble in the center of a flat plate and then tried to push that marble to the edge of the plate, the marble would move in a straight line, as long as the plate was still. But if the plate was spinning, the marble would follow a curved pattern as it traveled from the center to the edge. Winds passing to and from the North and South Poles and the equator are subject to this effect.

Imagine if a person were to stand at the North Pole and throw a ball far enough to reach the equator — say, to a person standing in Quito, Ecuador — the ball would not actually reach that person because it would not travel in a straight line. Particles traveling from the equator to the south experience a similar curve in the opposite direction. Here's how that determines the spinning pattern of hurricanes: The area at the center of a hurricane has very low pressure, so the higher-pressure air that surrounds the eye of a storm naturally heads towards that middle area.

But as the air rushes toward the center, it winds up moving in a curved path thanks to the Coriolis effect. This creates a circular spinning pattern as air travels from areas of high pressure to low pressure. For further explanation on how the effect influences hurricanes, check out the full video here :. And FYI, this phenomenon doesn't explain the circular direction that water travels in your toilet bowl after you flush.

A toilet bowl is too small to be affected by such a grand process. Correction: A previous version of this story mischaracterized the pressure dynamics of air in hurricanes. The description has since been amended for accuracy. Follow Tech Insider on Facebook and Twitter.