How does a periscope work?

A simple periscope can be done using two flat mirrors, inclined at 45 °. The light is reflected by the mirror from the top to the bottom. It is then possible to see an object over a wall, or over the water, when one is in a submarine.

The submarines have periscopes that allow you to see what's going on over the water when the device is submerged. Sometimes submarines sail by letting their periscope pass. But the longest of the periscopes, 27 m, is on land, in a laboratory in the United States where you can study nuclear reactors without exposing yourself to dangerous radiation.

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How do some fish produce electricity?

                         


About 250 kinds of fish can produce electric shock. This allows them to head into muddy waters and also kill their prey. The most powerful electric fish can emit shocks of several hundred volts, enough to stun a human. They have special muscles that act like batteries.
Some name of the fish that produces electricity:
Electric eel, Peters' elephantnose fish, Malapterurus electricus...

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What about cotopaxi?

From time to time it erupts because it is one of the largest active volcanoes in the world.
For 400 years it has erupted 50 times, the last eruption lasted from August 2015 to January 2016. Top of 5897 m, it is located in Ecuador.

Also:

Mauna Loa is the largest volcano in the world. It is on the Hawaiian Islands measuring 119 km at its base.

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What is a glacier?

A glacier is a moving ice field. It is found in the polar regions and in the high mantains, everywhere there is more snow in winter than it can melt and evaporate during the summer. The smooth mass slides slowly down the slopes, modeling the landscape and sculpting the valleys. If a glacier reaches the sea in a very cold area, huge blocks of ice blocks break up and form icebergs. The largest in the world are in Antarctica.

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What is an amphibian?

                         What is an amphibian?

It is sort of the intermediate step between fish and reptiles. Most spend the first part of their lives in water and their adult phase on earth. They have moist skin and lay their eggs in water or in a very humid environment. They live near water, especially in swamps, but can not survive in the sea
Amphibians are found all over the world, except in very hot regions.

Most of them have four legs, except for the Cecilies, who have none at all.

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Where is the Carpathian Mountains?

These mountains are located in central Europe. They follow the border between Slovakia and Poland and extend as far as Romania. Lower than the Alps; their highest peak only reaches 2655 m. They also have fewer lakes, waterfalls and glaciers.

Also:

• After Russia, the largest country in Europe is Ukraine. France is third.
• Europe owes its name to Europe, a princess of Greek myths. 

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Where was the kingdom of Benin?

The kingdom of Benin was in West Africa, south of the Niger River. 400 years ago, his people made beautiful objects in ivory, wood and bronze. By the year 1000, powerful African kingdoms such as Benin, Kanem-Bornou and Songhaii reigned over West Africa.

Also:

• Africa exports oil, diamonds, gold, and other minerals such as cobalt.
• South Africa produces most of the world's gold.
• Africa's crops include maize, cocoa, tea, cassava, ingame, coffee, sugar, vanilla, bananas and rubber.
• The crops of Africa are: maize, cocoa, tea, cassava, yam, coffee, sugar, vanilla, bananas and rubber.
• about a quarter of the world's forests are in Africa.
• about 40% of Africa's manufactured goods come from South Africa.

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What are the Everglades?

The Everglades are subtropical marshes in south Florida, southeast of the United States. Their area exceeds 7000 km². In places the cutting grass is sometimes 4 m high. Elsewhere, there are salt marshes and mangroves. Before the seminole Indians took refuge there around 1840, no one lived in this region. Partly drained for use in agriculture, the region is now a national park where you can see turtles, alligators and many species of birds.

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How does a volcano erupt?

During an eruption, magma (molten rocks) from the depths of the earth rises to the surface.
Lava (name given to the magma that is pushed outside), red and burning, flows from the volcano.
Smoke and ashes are spewed to the sky and darken.
An active volcano contains thick lava, which rises very slowly and can form a closing pellet. The pressure increases until the gases and ashes pierce it and blow it up, causing a huge explosion.

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The Komodo dragon

 Unlike the fabulous winged monsters of legends, the Komodo   dragon does not spit fire, nor does it fly.
 This massive animal with a big head and a long thick tail is the   largest of the current lizards. 
He lives on a few islands in Indonesia  and feeds on deer and wild   pigs. The Komodo Dragon was discovered by Western scientists in 1910.

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Bonsaï

                                                                  bonsaï

  

• It is a tree that grows in pot like a plant and is grown to be the reduced model of a tree. 

      (Native to Japan)

                                  

      Bonsai are planted in narrow pots and rationed (food). 
The roots and shoots are pruned when the tree grows. The branches are twisted and tied by threads so that the adult tree does not exceed 50 cm.
when mature, the plant looks like an old gnarled tree

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Why should we avoid a phalloides amanita?

Because it's a deadly dangerous fungus. It is best to avoid touching a wild mushroom, unless you know exactly which ones are harmless and which ones are dangerous.

The fly agaric is one of the deadliest mushrooms. His red hat makes it easy to avoid.

Fly agaric is very toxic. Formerly we used his juice to kill flies and bugs.

The word ''amanite '' comes from the Greek amanitès which designates a whole family of mushrooms.

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Which plants have no roots, leaves or flowers?

Lichens, which are an assemblage of algae and mushrooms living together. Some lichens grow in patches on stones and trees.
They grow very slowly and live very old (10,000 years). They are among the oldest living things and survive in places that are too bare, too dry, too cold or too hot for other plants.

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Why does the Puffball explode?

The giant Puffball is a big round mushroom. Its skin is paper-thin, swollen from the inside and explodes when a drop of water touches it, leaving a cloud of spores.
Most mushrooms produce a fruit, which is the part we see, the rest of the mushroom is underground or in wood. Some are edible, but others are poisonous.

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What is giant kelp?

It is the largest of the algae. It can measure up to 60 m long and when several kelp grow together they form an underwater forest. Kelp is an ideal shelter for many fish, lobsters and other marine creatures. There are several kinds of kelp, all are brown algae that live in cold waters.

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