11:02 PM Learn all about volcanoes, including how they are made, how to spot an old one and more! Includes an experiment! |
Learn all about volcanoes, including how they are made, how to spot an old one and more! Includes an experiment!Our earth is hot inside. Very hot rock, called "magma," is deep underground. Magma is a runny liquid, kind of like melted ice cream, but it is so hot that it smokes and steams. It is hot enough to melt steel. Now, that's hot! Sometimes, the magma in the earth builds up great pressure, and starts pushing upward. The pressure pushes the magma through a weak spot in the ground, and sometimes it rises up through "pipes," which are like tunnels. It can come from deep inside the earth all the way to the surface of the ground. It may push up the ground, forming a mountain. If it breaks through the top of the ground or the mountain it has created, a volcano is formed. The hot magma might spurt out the top of the volcano, like a fountain. Or, it might bubble very slowly out from a crack in the ground. That crack is called a "fissure." When magma comes out of the volcano or fissure, it is then called "lava." Sometimes, only smoke, gases and ashes come out of the volcano. There are many old volcanoes in the world. Long ago, they had lava coming out their tops. They have been quiet for a very long time and are "inactive." Other volcanoes in the world are quiet for a long time and then suddenly become "active." They belch out smoke and gases. They burp up ashes, and once in a while, lava comes out of them. When this happens, the volcano is said to be "erupting." ACTIVE VOLCANOES Active volcanoes can be found in many countries of the world. We don't need to be frightened of erupting volcanoes, because the smoking and spurting gases and ashes are warning signs that the volcano might erupt. These signs give people time to leave the area and get to a safe place away from the volcano. *********************************** Ask for permission before you try this experiment. You are about to see how pressure works. Like the pressure in the earth that builds up and finally bursts out as a volcano, you will make pressure build up, too! 1. Get a can of soda pop. Make sure you keep the top of the can pointed away from everybody's face. Don't open the can. 2. Now, shake up the can. Only shake it about 10 or 15 good shakes. 3. Pointing the top away from everyone, open the can. The soda will squirt and spray out! It is just like a volcano, only much smaller and not nearly as dangerous! When you shook up the can, you created pressure. When you opened the can, you released the pressure. LOOKING FOR VOLCANOES You might live in a part of the world where an active volcano is nearby. You already know where it is and what it looks like, but if there are no active volcanoes near you, how do you spot an old one? In many parts of the world, you may be able to see an old volcano. Volcanoes are shaped from the building up of layers of ash and lava. Old volcanoes come in three basic shapes. 1. Volcanoes that had very runny lava are low and flat, but you may be able to see the "lava beds," formed when the lava spread out and cooled. 2. Some volcanoes had lava that was so hot it burned up and only ash remains. These volcanoes now have a short and fat shape. 3. Volcanoes that had very thick lava are shaped like pointed cones. The lava ran slowly down their sides. Some of these volcanoes look like mountains with their tops cut off. ***** Hot water springs are often found near volcanoes. The same heat in the earth that melts the rock into magma, heats the water. These hot springs and pools may contain water that is near boiling! Sometimes, the only visible evidence of an old volcano is the kind of rock found in the area. Near the area of ancient volcanoes you usually see volcanic rocks. There are many kinds, some with bubbles and some that are very shiny like glass. Some may be made from ash and they are dull and powdery. Volcanic rocks come in many colors. They might be pink, red, green, black, reddish brown, gray, white, yellow or even purple! They may be very heavy or extremely light in weight. When you see some, just remember they all came from deep inside our earth! Maybe you should start a rock collection! ***** Our Wonderful Earth! |
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