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Case-lesson «The wonderful world of volcanoes»
Case-lesson «The wonderful world of volcanoes»

Category: Science, nature and man

The level (grade): 8 +

Subject: Natural phenomena

Objective: Uncover the secrets of volcanoes nature and existence

What information is waiting for me here?

  • What effect do volcanoes have on the environment and the world in general?
  • Why do volcanoes erupt?
  • Can we view volcanic geysers?
  • Are there volcanoes on other planets?
  • What the fundamental and practical knowledge will be useful to me?
  • What volcanoes are the most dangerous?
6 scans of the subjects, phenomena and practices:

What is a volcano? Where was it originated? How many volcanoes are there?

Even in ancient times, the Romans believed in gods, but Volcano was the most formidable of them. It took several thousand years since these times, but the amazing world of volcanoes has not disappeared. It is charming by its beauty each of us or scaring world. There were great volcanic catastrophes in Pompeii and many other places on the planet.

Let us go in a fantastic "journey" into the world of volcanoes, look at the history of their origin, the existence and dangers.


A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. Volcanoes are studied by science geology.

However, this phenomenon is so interesting to scientists that it was formed a separate branch of science devoted to volcanoes, and it became known as volcanology. Travelers are also always interested in volcanic activity. What causes volcanic eruptions?

In general, an active volcano can be described as:

Volcanoes are usually funnel-shaped with a recess at the top. When pressure rises in the middle of the volcano, in magma, the lava rises through the crater of the volcano and overflows. During this, the atmosphere can enter gases such as water vapor, carbon dioxide and sulfur dioxide. In addition, sometimes the other substances, such as hydrogen sulfide and hydrogen fluoride, fall into air. In any case, the effects of volcanic eruptions are very dangerous for the environment. After all, if eruption is powerful, the volcano is able to throw into the stratosphere gases and ash to a height of 16-20 meters. They are spread over thousands of kilometers.

Volcanoes can be divided into "historical" figure:


There are several types of volcanoes. Linear and central are the biggest group of volcanoes:


However, geologists have given a more complex classification of volcanoes:


What types of eruptions are there? There are: • Hawaiian eruptions are characterized by the effusive eruption of very fluid basalt-type lavas with low gaseous content. It can often make lava lakes, lava can spread over long distances. • Strombolian type – lava is denser and ejected from the crater. Typically cones of ash, volcanic bombs and lapilli are formed. • Plinian type – rare powerful explosions that can throw a figure to a height of 10km. • Pelean type – eruption, the hallmark of it is the formation of intrusive domes and "scorching clouds." • Gas (phreatic) type – the eruption, where only the volcanic gases reach crater, and there is an emission of solid rock. Magma is not observed. • Underwater type – underwater eruption. As usual, it is accompanied by emission of pumice. What are the relationships between volcanoes and geysers? Geyser is one of the later stages of volcanism.

Usually, the term "geyser" refers to a source with a very high water temperature. As a result is the eruption of boiling water in the middle of the geyser. Geysers have quite interesting mechanism of action.


First, water is collected in an underground cavity, located near a pocket of hot magma. As magma has very high temperature, water is heated, boils and explodes. Why is there an explosion?

Water on the surface has not reached the boiling temperature yet, but the temperature at the bottom has already had 120-125 C degrees. Because water boils at a depth, vapor mass emit layer of water on the surface by a large force. There is a fountain, which continues to operate for 1-2 minutes under the pressure of the water column. Then water completely disappears from the pits and refills it again. Geyser effect occurs every 30-40 minutes, or once a day.

There are few "pseudo-scientific myths" associated with geysers. Let us try to understand them.

There is an opinion that any geyser can be a volcano. In fact: the proximity to areas of volcanic activity and the presence magma chamber at depth for the existence of geysers are really needed. However, unlike in the volcano, magma in geysers only performs the function of water heating. The eruption of the geyser is not possible without vertical or inclined cracks in the ground tanks that are filled with groundwater, and the constant influx of these waters. Geysers erupt underground water. In fact: underground water - is, in fact, the water from melted snow and rainwater. It falls into the hydrothermal system, moving through underground aquifers. During the movement, water is heated by magma and comes to the surface in the form of a geyser or hot spring. This path may take a few hundred years, so this "weathered" water can be called underground.


Geyser spews a jet of steam and water column continuously.

In fact: There are four stages of geyser work: spout, gushing, soaring and filling or restoration of the water level in the channel. Each of these stages occupy different time - minutes or several hours, depending on the geyser size, shape and location in the ground.

It is difficult to determine if water jet appear soon. You need to know the specific nature of the geyser to predict that an eruption will start soon.

Life is impossible in boiling water geyser and near. In fact: It is not true! There are thermophilic blue-green algae there. This type of ancient organisms of Earth (they colonized the ponds around three billion years ago) prefers temperatures of over 45 ° C. In addition, a rare Chinese orchid grows on the slopes of geysers.

Soldier flies (Odontomyia Argentata) live near geysers. They crawl along the inner rocky vaults geysers, often getting into their small craft, and stay active after this. High temperature mode enhances the exchange of insects substances, and because of their development cycle is completed even if the lack of food and other adverse factors. The heat of the earth is used for breeding and poultry. Therefore, wagtail builds a nest and lays eggs in the warm soil. Due to this natural hatchery, chicks near geysers appear earlier than in other areas.


Water in geysers is most pure and healthy. In fact: Water in geysers may not be useful for humans, but even dangerous for them. It may contain toxic elements such as mercury, arsenic and antimony.


Make a comparative description of the geysers and volcanoes (you can submit it in the form of presentations, spreadsheets, infographics - practice your creative thinking). What the parameters for comparison do you use?


What are the most powerful volcanic eruptions known in the history? In 186 BC New Zealand had the largest volcanic eruptions in recorded history. In addition, what major eruptions have been in the world? That's "TOP-10":

However, the eruption of Mount Vesuvius is the most often mentioned, where Roman city of Pompeii, Herculaneum and Stabiae were destroyed.


Vesuvius has spawned a huge red-hot cloud of stones, ash and smoke up to 33 km altitude, highlighting at the same time the thermal energy, many times exceeding the one that stood out in the explosion of the atomic bomb over Hiroshima.

Systematic excavations in Pompeii began in 1860, the same time researchers found 40 bodies buried under the ashes. Historians have discovered that the neighborhoods of Vesuvius were destroyed by pyroclastic flows. Pliny the Younger, a Roman politician and writer, was a witness to the disaster, and described it in his notes: "a black and dreadful cloud bursting out in gusts of igneous serpentine vapour now and again yawned open to reveal long fantastic flames, resembling flashes of lightning but much larger." ...

However, volcanoes do not remain in the past and from time to time; the entire world's media spread information about the new eruptions of the volcano. For

The world’s most dangerous volcanoes:



Prepare a short report (presentation) about the one of the last volcanic eruptions. Do you remember how to pronounce the name of the volcano eruption in Iceland, which has been recently?

Seven volcanoes in the world - are a group of volcanoes, which are the highest in 7 different parts of the world. These include North America, South America, Europe, Asia, Australia, Africa and Antarctica. In Australia, the highest volcano is Giluwe, in Europe - Mount Elbrus, in South America - Aconcagua, in Africa - Kilimanjaro, in Antarctica - Sidley, in North America - Orizaba Peak. In fact, there are certain difficulties in defining the highest point of the volcano. On the world map volcanoes and volcanic activity zones are:


Volcanoes are the result of tectonic activity of our planet, the changes occurring in the lithosphere. In addition, the most active in this sense is a place of tectonic plate’s collision:


The thickness of earth's crust (the lithosphere) is about 1% of the radius of the globe. On land it is 70-80 kilometers, and in the depths of the oceans may be only 20 kilometers.

The mantle temperature is a thousand degrees. Closer to the core mantle temperature is higher, closer to the crust – less. Occurs mixing of the mantle can be because of the temperature difference: hot masses rise up, and cold - fall (as well as water begins to boil in a saucepan or kettle, but it happens a thousand times slower). Mantle is warmed up to enormous temperatures, but due to the Earth's center of enormous pressure it is not liquid and viscous, like a very thick resin. Lithosphere is floating in the viscous mantle, a little lost in it under the weight of its own weight.


Reaching the base of the lithosphere, weight mantle sometime moves horizontally along the solid stone "shell", but then cooled down; it goes down again towards the center of Earth. While mantle moving along the lithosphere, with it necessarily moves and pieces of the Earth's crust (lithosphere plates), and the individual pieces of mosaic stone crawl on top of each other.

Part of the plate, which was at the bottom is gradually sinking into the mantle, and begins to melt. This forms the magma - molten rock thick mass of gases and water vapor. Magma is lighter than the surrounding rock, so it slowly rises to the surface and accumulates in the so-called magma chambers. They are located mostly along the line of the plates’ collision.

Magma is more liquid than the mantle, but still is quite thick. Translated from the Greek "magma" means "thick paste" or "dough."

The behavior of red-hot magma in the magma chamber resembles yeast dough: magma expands, occupies the entire space and rises from the depths of the earth along cracks, trying to break free. As the dough raises the lid of the pan and flows over the edge, as magma breaks through the earth's crust in the weakest places, and breaks the surface. This is a volcanic eruption.


Compare the map of tectonic plates and volcanic activity. What do you think explains the relationship between them?


At the heart of the volcano eruption is pressure. The magma in the magma chamber is under pressure, as well as carbonated drinks in a closed bottle. In the place where the crust was "not closed", magma can escape from the Earth's interior, knock "plug" of the volcano, and the stronger was the "plug", the stronger will be the eruption of the volcano. Climbing up, the magma loses gases and vapors of water and turns into lava - carbon-depleted gas from magma.


In contrast to fizzy drinks, gases that are released during the eruption of the volcano are combustible, so they ignite and explode in the crater of the volcano. The power of the explosion of the volcano is so powerful that in place of the mountain after the eruption remains huge "funnel" (caldera), and if the eruption continues, directly in the cavity starts to grow a new volcano.

However, it happens that magma cannot find an easy way to go out to the surface of the Earth, while lava flows from volcanoes without any explosions. Like boiling porridge, gurgling, poured over the edge of the pan. In this type, volcanoes erupt in Hawaii. Magma does not always have the strength to come to the surface, and then it slowly solidifies at depth. In this case volcano cannot form.

After rapid degassing process, pressure in the magma chamber is reduced, and the eruption stops. The crater of the volcano closed solidified lava, but sometimes does not very firmly: in the magma chamber is hot enough, so the surface through cracks can escape the volcanic gases (fumaroles) or a jet of boiling water (geysers).

The result of the eruption of the volcano is lowering the air temperature. This is – the result of a thermodynamic process, which is used to characterize an important physical parameter status - entropy S. What are the thermodynamic processes?


These processes are described:


Volcanic eruption process can be regarded as cyclical, as at any time in the magma chamber could accumulate a large amount of magma eruption and then the process starts again.

Not only people are blamed in air pollution. As, for example, the eruption of Mount St. Helens in North America shown, the atmosphere is often polluted by the nature. Huge clouds of dust and gas in the eruption were visible for many kilometers, but the volcano was fraught with an invisible danger. According to the calculations of American scientists, it threw the radioactive gas radon total dose of 3 million curies. Which elements are contained in volcanic emissions? Here are some of the "main":


Volcanoes erupt huge mass of various toxic gases. Why these gases are considered to be poisons? After all, many of them and so are contained in natural environments. The response consists of two parts:


For example, a few years ago it was found that the Etna in Sicily emits sulfur dioxide more than 50 large coal-fired power plants. How much of this dangerous emission Mount St. Helens released into the atmosphere is still unknown. However, we know that sulfur dioxide in the atmosphere very quickly transformed into sulfuric acid. As a result, it may forms a layer of smog, weakening sunlight in the stratosphere.


Some volcanoes are sulfur-rich. For example, the volcano KawahIjen, located in East Java province. It is a source of sulfur raw materials, but in order to get it the miners have to climb to the top of the volcano to a height of 8660 feet to the mine in the crater, which is filled with deep molten lake of sulfuric acid in 650 feet deep. At night, the volcano turns into a lit light blue-violet mountain. Mystical light begins to rise from the depths of the crater. High-temperature liquid sulfur is flowing out of the lake, flashing blue flame, reaching 5 meters in height:

Another dangerous gas is chlorine. Volcanoes emit it mainly in conjunction with hydrogen, in the form of hydrogen chloride. For small eruptions gas remains in the lower atmosphere, quickly reacts with water, forming hydrochloric acid. Hydrochloric acid is a solution of hydrogen chloride in water (with account of hydrolysis)


But during the powerful eruptions, what was the eruption of Mount St. Helens, hydrogen chloride in a large amount shall be made in the stratosphere, where it can contribute to the destruction of the ozone layer, which protects us from harmful ultraviolet radiation from the sun. This is compounded by the formation of ozone holes.

The amount of chlorine entering the stratosphere during volcanic processes still does not get the right valuation. Scientists have found that magma is actively erupting volcano may contain chlorine 20-40 times longer than It was thought previously.

It was discovered during the eruption of the volcano in Alaska in 1976 Augustine. According to estimates, the volcano threw out 300 million tons of magma, containing up to 0.5 million tons of chlorine. It is believed that between 80 and 180 tons of chlorine got into the stratosphere. This ranged from 17 to 36% of the chlorine amount, which was in Freon, produced in the world in 1975. This is significant, because the world production of CFCs in that year peaked. After 1975, the production of CFCs was reduced due to the restrictions imposed in countries where the feared overproduction of substances used in refrigerators and aerosol cans. But despite all efforts, the dynamic of the formation of the ozone hole is:


Annually there is one major volcanic eruption every year. However, ozone in the stratosphere is highly variable and difficult to understand how these variations are associated with volcanic eruptions. Perhaps the release of chlorine is the natural processes of the global chemical equilibrium. These complex interactions are poorly understood. If the ozone in the stratosphere falls, it is hardly to blame only the CFCs, perhaps this fall is due to natural processes such as volcanic activity.

Is it possible to "create" the volcano itself? Yes, and chemistry will help!

The first method of "volcanocreativity":

This decomposition of ammonium dichromate is spectacular one of chemical reactions. It is accompanied by the formation of greenish chromium oxide (III), water and nitrogen. In fact, this is a reaction scheme of combustion:


The second method of "volcanocreativity":


During chemistry lesson spend a mini-investigation - compare two types of "mini-volcanoes" and write a report on the experiment. Do not forget to specify the starting materials and reagents, reaction products, their physical state and color, the reaction proceeds, is it exogenous or endothermic.

Cosmology / Astronomy

Are there volcanoes on other planets? There are!

Because of studying the lunar using spacecraft, it was revealed that the vast majority of lunar ring mountains, craters have percussive, meteoritic origin. But, nevertheless, clear traces of volcanic activity was found on the surface of our natural satellite. For example, the Moon widespread basaltic volcanic origin, there is also outlets lava. There is also reason to believe that the mass concentration - "mascons" discovered by artificial satellites of the Moon at the bottom of some lunar seas, are nothing more than a frozen lava tubes.


There are such formations on the lunar surface, which may be associated with volcanic processes more closely. This is so-called domes – peculiar round swellings, on top of which is the formation of sometimes resembling a volcanic caldera (the area around the crater collapse). Interestingly, these formations can be in the Earth. They are laccoliths, raising the earth's crust caused by volcanic activity foci. These include, for example, some of the mountains of the North Caucasus.

Obvious traces of volcanic activity can be found on satellite photos of Mercury - the closest planet to the Sun. Mercury's surface is almost completely covered with lots of craters. And even though these craters as the moon are impact origin, at the bottom of some of them are clearly visible traces of the outpouring of lava. Here, for example, Mercurian craters:


There are also a number of data that tell that Venus volcanic activity continues to this day. As is known, the temperature of the surface of the planet is approaching 500 ° Celsius. Apparently, such a high temperature is due to, above all, the action of the greenhouse effect. But it is possible volcanic processes, in particular, hot lava, may affect the temperature.


Analysis of new data on Mars, obtained mainly through the spacecraft showed that volcanic processes on this planet played a very significant role in the formation of relief. For example, some Martian craters have central peaks with a dark dot on the top. It is possible that they are extinct volcanoes.

There are mountains on Mars with respect to the volcanic nature of which there is no doubt, for example, Mount Olympus altitude of about 27 km.

For comparison, it suffices to recall that the highest mountain peak of the earth - Mount Everest - is less than 9 km. When in 1971 on Mars raging strongest dust storm, the cone of Mount Olympus towered over the dusty veil.

That is how it looks:

There are three giant extinct volcano in the same area, whose height is only slightly less. According to experts, this group of volcanic eruptions occurred tens or hundreds millions years ago. They were accompanied by the release of huge quantities of ash, probably covering now many lowland areas of the planet. The presence on Mars so high volcanic mountains shows great power of volcanic processes that make the planet's surface poured huge mass of matter.

Perhaps one of the most interesting discoveries made with the help of satellites, was the discovery on Jupiter's moon Io 9 active volcanoes. They throw dust and hot gases to a height of 200 km. Here's their eruption:

Are there geysers on other planets? The answer is the same - there are!

In 2009, the "Cassini" spacecraft NASA, made a flight around Saturn. During the flight by one of its outer moons - Enceladus - the device was able to take a picture of something unusual. On its surface it was able to detect giant cracks, of which the open space at a speed of 2250 km / h and pulled ice water geysers up to hundreds of kilometers.


Liquid water escapes to the surface and almost immediately freezes to form ice particles and snow - a phenomenon is called cryovolcanism. It should be noted that this phenomenon occurs only at the south pole of Saturn's moon, where there are narrow fissures in the planet's crust, known as "tiger stripes." Causes of what is so different from other moons Enceladus and the processes occurring in its interior are still unknown.

Lesson summary




A result of Case Knowledge Hypermarket can add the following findings of students:



What 3 sites helped to get information?






To help the student and coach:







Where to take information for the Case:











Locations of the lesson:

Case lesson takes place in the classroom. Carrying classes at the museum, park, library...




Teams of boys and girls.

The score of the competition between teams was…

Targets for them:

Follow the creative task: is there any volcanic activity in the positive aspects? What kind? Describe them in a free-form essay, you can use illustrations.

2. What are the physical and chemical phenomena linked to volcanic activity?

 The winner is team, which gave a greater number of correct answers.



Make a presentation about recent or most significant volcanic eruptions. Be sure to include a description of the geographical position of the selected volcano (you can mark it on a map). What impact this eruption has on the environment? And on the economic activity?


Duration of Case:

90 minutes(double lesson). 


Ability to circuit classes with student-double for: 



The results produced and competence:

  • Understanding the relationship of biological, chemical and physical processes occurring on Earth and other planets.
  • Knowledge of volcanic geography knowledge
  • The ability to quickly find, organize and analyze the received information.
  •  Ability to critically reflect and compare the received information, to establish cause-and-effect relationships in the example of tectonic and volcanic processes. 



Geology, magma, tectonic plate, the lithosphere, the caldera, the volcano, geyser, eruption, the mantle, the pressure, thermodynamic process, smog, ozone hole, crater



Grabowska Larissa L.


Took part in case apgrade:



The End

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