All about Cyclones

What are cyclones?

Cyclones ( or more properly called Tropical Cyclones) are a type of severe spinning(rotating) storm that occurs over the ocean near the tropics.
The word "Cyclone" just means 'turning wind with one eye. It relates to the word "Cyclops" that one eyed creature in an Ancient Greek story.

Tropical Cyclones have a number of characteristics like:

• They must have a wind speed greater than 119km/h
• They start in the tropics.

Did you know...

cyclones are also called hurricanes around the US. Cyclones are called typhoons near the South China sea (from the chinese word meaning 'big wind' )

Image: Courtesy of NOAA

Did you know that cyclones are actually the release of stored solar energy that rotates. The sun heats the ocean up and this creates the condition for a tropical cyclone to develop. Cyclones spin because the Earth is spinning. It's due to something called thecoriolis effect. The direction they spin depends on which hemisphere they are in. In the Southern hemisphere they spin in a clockwise direction and Northern hemisphere they spin in an anti-clockwise direction.

There are two main parts of the Earth's surface that cyclones affect. Land Sea Land - the obvious is the the land closest to the sea. Usually the land is subjected to high winds but also rain. This can result in flooding of low lying areas. The parts that join the land with the sea such as the coast might suffer erosion. For example sand may be washed away leaving bare rocks. Coral reefs can often be damaged. Most reefs can cope but if cyclones are too frequent then they don't have time to recover and could die. The wind along the coasts might tear down trees and cause damage to buildings. But sometimes the wind might help to disperse seeds (eg coconuts, and mangrove pods) Sea - the sea is typically suffers large waves which can cause problems for ships travelling in the area. The extra rainfall can dilute a part of the upper level of the water but this might not be a problem as the sea is being churned up all the time. In extreme cases a tornado can form over the sea and suck fish out of the sea and send them flying inland causing 'fish to rain down'

The effect on animals on land Animals that live on the land might be affected such as having their burrows flooded. For example a wombat. Animals that live on the coast may also be affected but in most cases they are well adapted to a rough sea life. Cyclones can cause flooding further inland many kilometres away from the main storm

Science made easy...Why Spiders do not stick to their webs.

Spiders lay down two types of webbing, says U of T zoology professor Darryl Gwynne: sticky and non-sticky. In fact, some spiders do get stuck in their own sticky webs, mainly by accident. But most are able to bypass the sticky strands and follow the safe trail of non-sticky webs laid down first for their own convenience.

Gwynne, who teaches at the University of Toronto at Mississauga, says web-building has several phases. A spider begins by attaching a single strand of silk horizontally between two supports, such as twigs or branches. It then builds an outside rim — almost like a bicycle wheel — and attaches spokes and a spiral from the centre to the outside of the web. These parts of the web are all composed of non sticky silk. With this frame — the foundation for a decent web — firmly in place, the spider adds the sticky strands, once again in a spiral pattern. This spiral is connected to the non-sticky spokes. "So, when a spider runs across from the centre of the web to grab a prey, it tends to go along a spoke, stepping on the bits that aren't sticky," Gwynne says. "And this essentially is the reason that spiders don't get stuck to their webs." 

River-Spanning Spider Web

Photograph courtesy Matjaz Kuntner

A river-spanning spider web dwarfs a park ranger in Madagascar in 2008. Made of the world's strongest known biological material, the web is the product of a new species, the Darwin's bark spider, which makes the world's largest webs of any single spider, new studies say.

Zoologist Ingi Agnarsson and colleagues have found Darwin's bark spider webs as wide as 82 feet (25 meters)—about as long as two city buses.

Dew on a Spiders web

Wire Spider web