Here is your short paragraph on Volcanoes !
A place from where hot molten lava along with hot gases, escapes from below the earth, usually found at mountain tops is what volcanoes are.
Mostly when the volcanic crater gets active is when these hot steam, ash, rock and lava come out.
Usually a volcano would erupt when the pressure and magma come together. Volcanoes are also found on other planets and not only on earth.
The word or name Volcano originated from the name Vulcan. Basically, a volcano erupts due to the high pressure that is built up inside the earth. An example is the Hawaii islands, which is the outcome of 5 volcanoes. There are basically two types of volcano. The safest of both forms is the Active Volcano where eruptions are regular. There are more than 500 known active volcanoes on Earth not counting the volcanoes that happens under the sea.
Next is the dormant volcano where it has not erupted for many years. However, they are active inside. A volcano is coined extinct when it has been dormant for years and the chances of being active is no more.
The liquid that are inside the rock, when they burst out and flow it is called the lava. Fresh lava would have a temperature between 700 degree Celsius to 1200 degree Celsius and would be red hot as it flows. Volcanoes are generally concentrated at the edges of the continents, beneath the sea forming long mountain ranges or along an island chain.
When volcanoes erupt, they do have serious effects on the people and land nearby. The destruction is very vast and huge. However, some of the plus point would include increase in fertility of soil; metals like copper, zinc, and silver, gold are all found from remnants of these volcanoes over the past years.
Over the years volcanoes does bring both good and bad effects and one need to make sure they are on the safer side and hope that such eruptions would not harm man and cause deaths and other destructions.