Volcanoes

A volcano is an opening, or rupture, in a planet's surface or crust, which allows hot, molten rock, ash, and gases to escape from below the surface. Volcanic activity involving the extrusion of rock tends to form mountains or features like mountains over a period of time.

On May 18th, 1980 the eruption of Mount St. Helens in southwest Washington state disrupted the lives of thousands and changed more than 200 square miles of rich forest into a grey, lifeless landscape. Now, more than twenty-six years later, the land around the mountain is slowly healing. Nature may be covering the scars of the 1980 eruption, but many people will never forget what happened that spring day.

The different parts of a Volcano

The image below shows the different parts of a volcano.

Magma - Molten rock beneath Earth's surface.

Parasitic Cone - A small cone-shaped volcano formed by an accumulation of volcanic debris.

Sill - A flat piece of rock formed when magma hardens in a crack in a volcano.

Vent - An opening in Earth's surface through which volcanic materials escape.

Flank - The side of a volcano.

Lava - Molten rock that erupts from a volcano that solidifies as it cools.

Crater - Mouth of a volcano - surrounds a volcanic vent.

Conduit - An underground passage magma travels through.

Summit - Highest point; apex

Throat - Entrance of a volcano. The part of the conduit that ejects lava and volcanic ash.

Ash - Fragments of lava or rock smaller than 2 mm in size that are blasted into the air by volcanic explosions.

Ash Cloud - A cloud of ash formed by volcanic explosions.

Types of Volcanoes

There are 3 different types of volcanoes:


1. Active - eruptions can be anytime and often.

2. Dormant - has been a while since it has erupted, but could at anytime.

3. Extinct, meaning it hasn't erupted in a very long, long time so it probably won't ever again.


Shapes of Volcanoes

How many different shapes of volcano are there?


The type of magma in the earth creates four different types volcanoes:

Shield Volcano - flat

If the magma is runny, the gas can escape easily and there will not be an explosion. The magma just comes out of the mountain and flows down the sides.

Shield volcanoes are shaped like a bowl or shield in the middle with long gentle slopes made by the lava flows.

Examples include the volcanoes in Hawaii and Mount Etna.








Composite Volcano - tall and thin

If the magma is thick and sticky (like honey), the gas cannot escape, so it builds up and up until it explodes sending out huge clouds of burning rock and gas.

Composite volcanoes are steep-sided volcanoes composed of many layers of volcanic rocks, usually made from thick sticky lava, ash and rock debris (broken pieces).

Composite volcanoes are also known as strato-volcanoes.

Examples include Mount Fuji in Japan, Mount St. Helens and Mt. Etna in Italy.


Cinder cones

Cinder cones are circular or oval cones built from erupting lava that breaks into small pieces as it shoots into the air. As small pieces fall back to the ground, they cool and form cinders around the vent.










Lava domes

Lava domes are formed when erupting lava is too thick to flow and makes a steep-sided mound as the lava piles up near the volcanic vent.







SUBMARINE ERUPTIONS

A submarine eruption is a type of volcanic eruption where lava erupts under an ocean. Most of the Earth's volcanic eruptions are submarine eruptions, but few have been documented because of the difficulty in monitoring submarine volcanoes. Most submarine eruptions occur at mid-ocean ridges and near hotspots.
1. Water vaper cloud

2. Water

3. Stratum

4. Lava flow

5. Magma condiut

6. Magma chamber

7. Dike

8. Pillow lava

ACTIVITIES ABOUT VOLCANOES

Crossword (easy) -----> with keys

Crossword (medium) -----> without keys: Send me your answers!!

Wordsearch -----> with keys

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Quiz -----> without keys: Send me your answers!!

Click here to read a transcription.

Try to guess the missing words (15) and send me your answers!
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Moon's Eclipses and Moon's Phases

A lunar eclipse occurs when the moon passes behind the earth such that the earth blocks the sun’s rays from striking the moon. This can occur only when the Sun, Earth and Moon are aligned exactly, or very closely so, with the Earth in the middle. Hence, there is always a full moon the night of a lunar eclipse.

The type and length of an eclipse depend upon the Moon’s location relative to its orbital nodes. The next total lunar eclipse occurs on December 21, 2010. Unlike a solar eclipse, which can only be viewed from a certain relatively small area of the world, a lunar eclipse may be viewed from anywhere on the night side of the Earth. A lunar eclipse lasts for a few hours, whereas a total solar eclipse lasts for only a few minutes at any given place.

The Moon orbits Earth about once every 29 and a half days. As it circles our planet, the changing position of the Moon with respect to the Sun causes our natural satellite to cycle through a series of phases: New Moon > New Crescent > First Quarter > Waxing Gibbous> Full Moon > Waning Gibbous > Last Quarter > Old Crescent > New Moon (again).

The phase known as New Moon can not actually be seen because the illuminated side of the Moon is then pointed away from Earth. The rest of the phases are familiar to all of us as the Moon cycles through them month after month.

When the Moon is Full, it rises at sunset and is visible all night long. At the end of the night, the Full Moon sets just as the Sun rises. None of the Moon's other phases have this unique characteristic. It happens because the Moon is directly opposite the Sun in the sky when the Moon is Full. Full Moon also has special significance with regard to eclipses.

Types of Lunar Eclipses

1. Penumbral Lunar Eclipse. The Moon passes through Earth's penumbral shadow. These events are of only academic interest because they are subtle and hard to observe.

2. Partial Lunar Eclipse. A portion of the Moon passes through Earth's umbral shadow. These events are easy to see, even with the unaided eye.

3. Total Lunar Eclipse. The entire Moon passes through Earth's umbral shadow. These events are quite striking due to the Moon's vibrant red color during the total phase (totality).

Now you might be wondering "If the Moon orbits Earth every 29.5 days and lunar eclipses only occur at Full Moon, then why don't we have an eclipse once a month during Full Moon?". I'm glad you asked! You see, the Moon's orbit around Earth is actually tipped about 5 degrees to Earth's orbit around the Sun. The Moon spends most of the time either above or below the plane of Earth's orbit.

When an eclipse of the Moon takes place, everyone on the night side of Earth can see it.

Why is the Moon Red During a Total Lunar Eclipse?

During a total lunar eclipse, the Earth blocks the Sun's light from reaching the Moon.

While the Moon remains completely within Earth's umbral shadow, indirect sunlight still manages to reach and illuminate it. However, this sunlight must first pass deep through the Earth's atmosphere which filters out most of the blue colored light.

The remaining light is a deep red or orange in color and is much dimmer than pure white sunlight.

Enjoy this video about Moon's eclipses!

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Exercises about Lunar and Solar eclipses

Solar Eclipse

A solar eclipse occurs when the moon passes between the Sun and the Earth so that the Sun is fully or partially covered. This can only happen during a new moon, when the Sun and Moon are in conjunction as seen from the Earth. At least two and up to five solar eclipses can occur each year on Earth, with between zero and two of them being total eclipses. Total solar eclipses are nevertheless rare at any location because during each eclipse totality exists only along a narrow corridor in the relatively tiny area of the Moon's umbra.

A total solar eclipse is a spectacular natural phenomenon and many people travel to remote locations to observe one.

In ancient times, and in some cultures today, solar eclipses have been attributed to supernatural causes. Total solar eclipses can be frightening for people who are unaware of their astronomical explanation, as the Sun seems to disappear in the middle of the day and the sky darkens in a matter of minutes.

There are three types of solar eclipses:

A total eclipse occurs when the Sun is completely obscured by the Moon. The intensely bright disk of the Sun is replaced by the dark silhouette of the Moon, and the much fainter corona is visible. During any one eclipse, totality is visible only from at most a narrow track on the surface of the Earth. The reason each total eclipse is only visible over a small part of the globe is because the Moon's shadow is relatively small when it falls on the Earth.

An annular eclipse occurs when the Sun and Moon are exactly in line, but the apparent size of the Moon is smaller than that of the Sun. For this reason, the Sun appears as a very bright ring, or annulus, surrounding the outline of the Moon. Another factor determining the type of eclipse is the elliptical shape of the Moon's orbit. This means that when the Moon is further away than average, it does not completely cover the Sun. This leaves a ring, or annulus of the solar disc exposed, hence the name annular eclipse.

A partial eclipse occurs when the Sun and Moon are not exactly in line and the Moon only partially obscures the Sun. This phenomenon can usually be seen from a large part of the Earth outside of the track of an annular or total eclipse. However, some eclipses can only be seen as a partial eclipse, because the umbra never intersects the Earth's surface, passing above the Earth's polar regions.

The Sun's distance from the Earth is about 390 times the Moon's distance, and the Sun's diameter is about 400 times the Moon's diameter. Because these ratios are approximately the same, the Sun and the Moon as seen from Earth appear to be approximately the same size.

However, spectacular eclipses will not grace the skies of the Earth forever.
Due to tidal friction, the Moon is slowly drawing away from the Earth at a rate of four centimetres (1.6 inches) a year. So, in time, it will be too far away to just fit over the Sun's disc and all eclipses will be of the annular type.
Our distant descendants, if they are still around in a billion years time, will be the poorer for not having total eclipses to admire.

Here you have two flash animation related to Solar Eclipses



And the second one

For further information, please watch the video!

Please, you can download the worksheet by clicking here

LET'S PLAY BACKGAMMON! (2º ESO - Bilingüe)

BACKGAMMON RULES

- SETUP -

Backgammon is a game for two players, played on a board consisting of twenty-four narrow triangles called points. The triangles alternate in color and are grouped into four quadrants of six triangles each. The quadrants are referred to as a player's home board and outer board, and the opponent's home board and outer board. The home and outer boards are separated from each other by a ridge down the center of the board called the bar.

Figure 1. A board with the checkers in their initial position.

The points are numbered for either player starting in that player's home board. The outermost point is the twenty-four point, which is also the opponent's one point. Each player has fifteen checkers of his own color. The initial arrangement of checkers is: two on each player's twenty-four point, five on each player's thirteen point, three on each player's eight point, and five on each player's six point.
Both players have their own pair of dice and a dice cup used for shaking. A doubling cube, with the numerals 2, 4, 8, 16, 32, and 64 on its faces, is used to keep track of the current stake of the game.

- OBJECT OF THE GAME -

The object of the game is move all your checkers into your own home board and then bear them off. The first player to bear off all of their checkers wins the game.

Figure 2. Direction of movement of White's checkers. Red's checkers move in the opposite direction.

- MOVEMENT OF THE CHECKERS -

To start the game, each player throws a single die. This determines both the player to go first and the numbers to be played. If equal numbers come up, then both players roll again until they roll different numbers. The player throwing the higher number now moves his checkers according to the numbers showing on both dice. After the first roll, the players throw two dice and alternate turns.
The roll of the dice indicates how many points, or pips, the player is to move his checkers. The checkers are always moved forward, to a lower-numbered point. The following rules apply:

• A checker may be moved only to an open point, one that is not occupied by two or more opposing checkers.


• The numbers on the two dice constitute separate moves. For example, if a player rolls 5 and 3, he may move one checker five spaces to an open point and another checker three spaces to an open point, or he may move the one checker a total of eight spaces to an open point, but only if the intermediate point (either three or five spaces from the starting point) is also open.

Figure 3. Two ways that White can play a roll of

• A player who rolls doubles plays the numbers shown on the dice twice. A roll of 6 and 6 means that the player has four sixes to use, and he may move any combination of checkers he feels appropriate to complete this requirement.
  
• A player must use both numbers of a roll if this is legally possible (or all four numbers of a double). When only one number can be played, the player must play that number. Or if either number can be played but not both, the player must play the larger one. When neither number can be used, the player loses his turn. In the case of doubles, when all four numbers cannot be played, the player must play as many numbers as he can.

- HITTING AND ENTERING -

A point occupied by a single checker of either color is called a blot. If an opposing checker lands on a blot, the blot is hit and placed on the bar.
Any time a player has one or more checkers on the bar, his first obligation is to enter those checker(s) into the opposing home board. A checker is entered by moving it to an open point corresponding to one of the numbers on the rolled dice.
For example, if a player rolls 4 and 6, he may enter a checker onto either the opponent's four point or six point, so long as the prospective point is not occupied by two or more of the opponent's checkers.

Figure 4. If White rolls with a checker on the bar, he must enter the checker onto Red's four point since Red's six point is not open.

If neither of the points is open, the player loses his turn. If a player is able to enter some but not all of his checkers, he must enter as many as he can and then forfeit the remainder of his turn.

After the last of a player's checkers has been entered, any unused numbers on the dice must be played, by moving either the checker that was entered or a different checker.

- BEARING OFF -

Once a player has moved all of his fifteen checkers into his home board, he may commence bearing off. A player bears off a checker by rolling a number that corresponds to the point on which the checker resides, and then removing that checker from the board. Thus, rolling a 6 permits the player to remove a checker from the six point.
If there is no checker on the point indicated by the roll, the player must make a legal move using a checker on a higher-numbered point. If there are no checkers on higher-numbered points, the player is permitted (and required) to remove a checker from the highest point on which one of his checkers resides. A player is under no obligation to bear off if he can make an otherwise legal move.

Figure 5. White rolls
and bears off two checkers.A player must

have all of his active checkers in his home board in order to bear off. If a checker is hit during the bear-off process, the player must bring that checker back to his home board before continuing to bear off. The first player to bear off all fifteen checkers wins the game.

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Play backgammon against computer!!!

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Temperatures scales

Temperature is a measure of molecular motion

Air temperature is one of those things that everyone is familiar with, which turns out to be more complicated than it might seem at first.

A thermometer actually measures the average kinetic energy of the various gas molecules that make up the air around it - let's call them "air molecules."

As you can see in the graphic on the left, air molecules in colder air move slowly compared to those in warmer air. The kinetic energy of an air molecule is directly proportional to the velocity of the molecule.

This means that colder air has less kinetic energy than warmer air.
When air molecules collide with a thermometer, kinetic energy is transferred from the air molecules to the glass and then to the mercury molecules inside the thermometer.
As the mercury molecules begin moving faster they move farther apart, pushing the mercury up in the thermometer.

In colder air, the energy from the air molecules colliding with the thermometer transferring to the mercury molecules is less than the energy from warmer air. As a result, the mercury molecules move slower in the colder air and the mercury inside the thermometer does not expand as far up the tube as it does in the warmer air.

Temperature is the level of heat in a gas, liquid, or solid. Three scales are commonly used for measuring temperature. The Celsius and Fahrenheit scales are the most common. The Kelvin scale is primarily used in scientific experiments.


Celsius Scale
The Celsius scale was invented in 1742 by the Swedish astronomer, Anders Celsius. This scale divides the range of temperature between the freezing and boiling temperatures of water into 100 equal parts. You will sometimes find this scale identified as the centigrade scale. Temperatures on the Celsius scale are known as degree Celsius (ºC).

Fahrenheit Scale
The Fahrenheit scale was established by the German-Dutch physicist, Gabriel Daniel Fahrenheit, in 1724. While many countries now use the Celsius scale, the Fahrenheit scale is widely used in the United States. It divides the difference between the melting and boiling points of water into 180 equal intervals. Temperatures on the Fahrenheit scale are known as degree Fahrenheit (ºF).

Kelvin Scale
The Kelvin scale is named after William Thompson Kelvin, a British physicist who devised it in 1848. It extends the Celsius scale down to absolute zero, a hypothetical temperature characterized by a complete absence of heat energy. Temperatures on this scale are called Kelvins (K).

Converting Temperatures
It is sometimes necessary to convert temperature from one scale to another. Here is how to do this.

To convert from ºC to ºF use the formula: ºF = ºC x 1.8 + 32.
To convert from ºF to ºC use the formula: ºC = (ºF-32) / 1.8.
To convert from K to ºC use the formula: ºC = K – 273.15
To convert from ºC to K use the formula: K = ºC + 273.15.
To convert from ºF to K use the formula: K = 5/9 (ºF – 32) + 273.15.
To convert from K to ºF use the formula: ºF = 1.8(K – 273.15) + 32.

Renewable and non renewable energy (2º ESO Bilingüe)

Si picháis aquí podéis ver el excelente trabajo realizado por Gema Muñoz y Rocío Abreu de 2º CD Bilingüe que expusieron en clase.

Nuestro lector, Jeffrey, nos explicó este tema de las energías renovables y no renovables (repitiendo la pronunciación de renewable y sources mil veces...) con esta presentación hecha por él mismo.

Las actividades que hemos visto en este tema son estas

Newton´s Law of Motion (2º ESO Bilingüe)

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