jueves, 24 de febrero de 2011


Pythagoras theorem is the relation among the hypotenuse and the other two sides of a right triangle:

In any right triangle, the area of the square whose side is the hypotenuse (the side opposite the right angle) is equal to the sum of the areas of the squares whose sides are the two legs (the two sides that meet at a right angle).

  • For 1º, 2º and 3º ESO click HERE to find  proofs , examples, questions and activities about this theorem.
  • Trigonometry functions and other triangle topics for 4º ESO and 1º Bach in this WEBSITE.
These links show many proofs of Pythagorean Theorem:
  1. http://www.cut-the-knot.org/pythagoras/index.shtml
  2. http://www.math.ubc.ca/~cass/euclid/java/html/pythagoras.html

lunes, 21 de febrero de 2011


History of the periodic table

Although elements such as gold, silver, tin, copper, lead and mercury have been known since antiquity, the first scientific discovery of an element occurred in 1649 when Hennig Brand discovered phosphorous. By 1869, a total of 63 elements had been discovered. As the number of known elements grew, scientists began to recognize patterns in properties and began to develop classification schemes. 
In 1817 Johann Dobereiner proposed that nature contained triads of elements the middle element had properties that were an average of the other two members when ordered by  the atomic weight (the Law of Triads).
In 1864 John Newlands published his version of the periodic table and proposed the Law of Octaves (by analogy with the seven intervals of the musical scale). This law stated that any given element will exhibit analogous behavior to the eighth element following it in the table.
In 1869 Russian chemist Dimitri Mendeleev started the development of the periodic table, arranging chemical elements by atomic mass. He predicted the discovery of other elements, and left spaces open in his periodic table for them. Mendeleev grouped the elements in a table that had both rows and columns

Unknown to Mendeleev, Lothar Meyer was also working on a periodic table. Although his work was published in 1864, and was done independently of Mendeleev, few historians regard him as an equal co-creator of the periodic table. For one thing, Meyer's table only included 28 elements. Furthermore, Meyer classified elements not by atomic weight, but by valence alone. Finally, Meyer never came to the idea of predicting new elements and correcting atomic weights. Only a few months after Mendeleev published his periodic table of all known elements (and predicted several new elements to complete the table, plus some corrected atomic weights), Meyer published a virtually identical table. While a few people consider Meyer and Mendeleev the co-creators of the periodic table, most agree that, by itself, Mendeleev's accurate prediction of the qualities of the undiscovered elements lands him the larger share of credit. In any case, at the time Mendeleev's predictions greatly impressed his contemporaries and were eventually found to be correct.
In 1914 Henry Moseley found a relationship between an element's X-ray wavelength and its atomic number (Z), and therefore resequenced the table by nuclear charge rather than atomic weight.

The modern periodic table of elements is based on Mendeleev's observations; however, instead of being organized by atomic weight, the modern table is arranged by atomic number (Z).  As one moves from left to right in a row of the periodic table, the properties of the elements gradually change.  At the end of each row, a drastic shift occurs in chemical properties. The next element in order of atomic number is more similar (chemically speaking) to the first element in the row above it; thus a new row begins on the table. 

Rows in the periodic table are called periods.  As one moves from left to right in a given period, the chemical properties of the elements slowly change.  Columns in the periodic table are called groups.  Elements in a given group in the periodic table share many similar chemical and physical properties.  The link below will open a copy of the periodic table of elements with  information about them. 

Structure Practical activities

Which form is stronger?
Explore with a sheet of paper the strength of accordion-pleated sheets compared to simple folded sheets.
  • Two identical sheets of paper
  • Cents
  • Notebook
Fold one sheet accordion-fashion along its length and make a bridge between two books.
Fold the other in half lengthwise, then again in half lengthwise. Be sure the two papers are the same length. Make this paper bridge two books.
Working in pairs, have one student add cents one by one to the bridges; have the other student record the number of cents added before the bridges collapse. Which folded shape is stronger?

Bridges good enough to eat!
Have the students construct bridges of pasta to span 30 centimetres. Remind them that this will mean the bridge has to be longer than 30 centimetres. If the class is old enough, emphasize triangles as being very stable shapes. Suggest that they look at pictures of bridges to see how the triangles fit together. Have a contest to find the strongest bridge, if the students do not mind having their bridge broken.


Etymological connection between Latin, English and Spanish languages


Write the name in English and in Spanish in your notebook . Look at the similar and diferent words.


Solis dies

Lunae dies

Mercurii dies

Iovis dies

Veneris dies

Saturni dies













Structure´ activity

1º Copy this activity in your notebook and fill in the blanks in these statements.

(a) The two main kinds of structures are _______ and _______ structure.
(b) If a frame structure has no 'skin' on it, it is  called an ___________frame  structure
(c) A structure that relies upon the shape it has been moulded into to give it its strength is  called a ________ structure.
(d) Loads can be  _______ (non-moving ) or _______ (moving).
(e) Tension, compression, shear, torsion and  bending are all types of ____________
(f) All these forcesmust be catered for in _________structures.
(g) An object is in tension if it is being ______
(h) An object is in compression if it is being_______
(i) An everyday item that cuts using a shear force is a ________
(j) Torsion is a _________ force
(k) If a beam is bent, the top surface is in ___ and the bottom surface is in ____
(l) ____ is a force that tries to stop one surface from sliding against another.
(m) When oil or grease is added to reduce friction, it is called a _________
(n) A long, rigid piece of wood or metal used to support a load across a gap is called a ______
(o) The use of triangles to strengthen a frame is called _____
(p) A common structure often found across water is a ______
(t) Little metal balls that reduce friction and allow bicycle wheels and pedals to move smoothly are called ___
Word: Open frame, Stretching, Static, Shell, forces, Scissors, compression, Beam, Bridge traction, friction,  Designing , lubricant, frame, dynamic, twisting, triangulation, bearings.

The Russian Revolution

The Russian Revolution

The Russian Revolution was the most important revolution of the 20th century, and was one of the most important revolutions in the history of the world.  I would place it as the third most important revolution after the American and French Revolutions. Like the American Revolution, and most other revolutions, the Russian Revolution was a revolution against economic oppression. In addition to this, the Russian Revolution started out as a revolution for democracy.
So, if the Russian Revolution started out being for democracy then what happened?
Basically Russia came into the 20th century as an extremely oppressed country that was ruled by the Czars. Russia was a feudal dictatorship. The people of Russia were horribly oppressed, poor, starving, cold, and without any real direction or hope.  Essentially, Russia had never undergone the liberal revolutions that took place in Europe (starting with the French Revolution), which had established liberal democracy and capitalism there.  Russia remained as one of the last vestiges of Medieval European society.
Through acts of “terrorism” and rebellion a small group of revolutionaries overthrew the Czars. Then Russia went into a stage of anarchy and turmoil, out of which the Bolshevik Party of Lenin emerged as the dominant political force.
Lenin and many of the Bolsheviks were not in Russia at the time of the Revolution. Some of them were from Russia originally but had left, while some were not from Russia at all.  They were all Marxists and socialist revolutionaries that had been living in Europe studying science, economics, sociology, history, etc.  from a Marxist perspective.  The Bolsheviks did not cause the overthrow of the Russian government; they came in after the overthrow with the plan of putting Marxist revolutionary theory to practice.  Their plan from the beginning was to develop Russia in such a way as to spread social revolution throughout Europe and eventually the world.  The biggest political opponents of the Bolsheviks in Russia, aside from the Czars, were the Mensheviks and Social Democrats, both Marxist groups who also supported Socialism, but were less militant.  What is important to understand about the Russian Revolution is that some of the biggest opponents to the Bolsheviks were other Communists.  The "brand" of Communism that was promoted by the Bolsheviks was by no means representative of all Communist ideology.   Bolshevik ideology was the least tolerant and most revolutionary form of Marxist ideology.
The Bolsheviks overthrew the remaining powers of the dictatorship in the October Revolution and began reforms by creating “Soviets”. Soviets were legislative assemblies of publicly elected officials that were to administer the activities of Workers, Peasants, and Soldiers.
The Constitution of the U.S.S.R.:
In addition to launching an attack on private property they did something else that upset countries around the world, and that was to make public all of the secret information that was contained in the Russian government files. They exposed all of the secret treaties that the Russian Czars had made with various countries as well as other information that the Russian government had acquired through its own intelligence operations. They did this because they felt that humanity should progress through honesty and they wanted to expose the corruption of other capitalists countries as well as of the old Russian regime.
These actions only added to the international opposition to the situation in Russia.  After World War I was over 21 countries from all over the world, including America, began supporting a counter-revolution in Russia in an attempt to stop the Bolshevik revolution. At this time Russia entered a stage of Civil War between the Reds and the Whites.
The Red Army was headed the by Leon Trotsky of the Bolsheviks and the White Army was headed by the Czars and was supported by the international community. This conflict led to an increasing degree of stress on the Reds and caused the Reds to become more dictatorial and militant as a defensive measure. The path that they took during the Civil War was known as "War Communism. "
In 1918 American President Woodrow Wilson sent 12,000 American troops to Russia to fight on the side of the Czars against the Red Army.  Interestingly, the American forces in Russia suffered more attacks and problems from the White Army than from the Red Army.  The American commanders in the field reported that the Czarist reign of terror was far more horrific and disturbing that the actions of the Reds.  The American forces also discovered that the vast majority of Russians sympathized with the Bolsheviks and supported the revolution.  In the end, the American troops were brought home without any fanfare, and the ordeal was considered one of the most ill-conceived interventions in American history up to that time.  Major General Graves, who lead the expedition, was accused of being a "Red sympathizer" and was generally disgraced after the event.
For more on this see:
Two distinct views emerged from the Russian revolutionaries.
One was that Russia was incapable of undergoing a socialist revolution and that according to Marxist theory Russia would first have to establish a capitalist system to develop its economy.  During the time that Russia was developing its capitalist economy it was intended that socialist revolutionaries should attempt to promote socialist revolution in developed countries, particularly in developed Europe such as France and Germany, and America as well, which would all be supported by the Russia government.
The opposing view to this was that a socialist state should be forced upon Russia and that Russia should lead the world by example in the matter of socialism. Stalin was a major supporter of this idea of "national socialism", which was contrary to the views of many of the Bolsheviks, including Lenin and Trotsky, two of the major figures in the Bolshevik Revolution.
The Marxist theory of socialism stated that socialism would not be possible to support in a single country, but that socialism required a global revolution so that all countries could work together through the use of shared resources and shared labor in order to provide enough goods to satisfy the demands of all people. The revolutionaries were genuine in their desire to attempt to bring about this condition, which is why they made certain that Russia was to have a strong policy against imperialism. They felt that in order for a true social revolution to take place it would have to be won through education of the people not through the force of war.
In 1918 Lenin was shot by a female Russian Socialist, Fanya Kaplan, who believed that Lenin had betrayed the Revolution and was not promoting Socialism.
In 1921 the Soviet Congress voted to institute a "New Economic Policy", known as the NEP.  Lenin was highly influential in the development of the NEP, which was largely a concession to capitalists and property owners.  The NEP allowed for the development of a free-market system and privatized production.
As Lenin’s health declined Stalin, as General Secretary, took increasing control over the party and at that time the democratic and open nature of the Russian system began to slip away. Stalin began removing his political opponents from the soviets and took on an authoritarian position.  Lenin tried to get the cooperation of Leon Trotsky to oppose Stalin but it was too late, Stalin had already consolidated too much power.  Prior to his death, Lenin not only warned against the leadership of Stalin, but he also urged that the Soviet system become more open and democratic.
Prior to his death Vladimir Lenin warned against Stalin's powers and urged that he be removed from his position.   Lenin wrote:
I think that the fundamental factor in the matter of stability—from this point of view—is such members of the Central Committee as Stalin and Trotsky.  The relation between them constitutes, in my opinion, a big half of the danger of that split, which might be avoided, and the avoidance of which might be promoted, in my opinion, by raising the number of members of the Central Committee to fifty or one hundred.

Comrade Stalin, having become General Secretary, has concentrated an enormous power in his hands; and I am not sure that he always knows how to use that power with sufficient caution.  On the other hand, Comrade Trotsky, as was proved by his struggle against the Central Committee in connection with the question of the People’s Commissariat of Ways and Communications, is distinguished not only by his exceptional abilities—personally he is, to be sure, the most able man in the present Central Committee—but also by his too far-reaching self-confidence and a disposition to be too much attracted by the purely administrative side of affairs.

These two qualities of the two most able leaders of the present Central Committee might, quite innocently, lead to a split; if our party does not take measures to prevent it, a split might arise unexpectedly.
- Lenin 1922




In 2011 is celebrated the international year of chemistry. You can see all the activities scheduled for this event on this  website

domingo, 20 de febrero de 2011

Activities Electricity

Learning circuits



1. The following document shows why the Industrial Revolution stars in U.K.

- Choose one of them and explain it.

Modern Times, Belgian Movie Poster, 1936 Láminas2. This is a factory scene from MODERN TIMES.                      

Once you have seen the scene answer the follows questions:
- What does this film criticizes?
- What new way of work appears?
- When does it begin?
- What is the consequence for workers? Tell three examples (seem in the film)


In the Famous Curves Index, URL: http://www-history.mcs.st-andrews.ac.uk/Curves/Curves.html click on the name :

  1. Circle
  2. Ellipse
  3. Hyperbola
  4. Parabola
Write in your notebook the cartesian equation of these curves. 
To experiment interactively with these curves, click on "If your browser can handle JAVA code, click HERE" to see the changes on the curves if changes the equations coefficients. Write in your notebook the changes you see.

miércoles, 16 de febrero de 2011


In this URL http://www-history.mcs.st-and.ac.uk/Indexes/Greeks.html

  1. Read in the list of Greek Mathematicians Pythagoras and Euclid biographies and write in your notebook the most important contributions to the Mathematics.
  2. Read the article " The teaching of mathematics in Ancient Greece" and write the differences with te teaching in the present.

martes, 8 de febrero de 2011

lunes, 7 de febrero de 2011


This animation takes us inside the human cell to provide a closer look at the microscopic level. It was by studying the chromosomes inside the cell that led James Watson and Francis Crick to discover the structure of DNA, which led to their Nobel Prize in medicine in 1962.


You can practise the learned      here



Historical Overview of Spain
Around 1100 BC, Phoenicians from present-day Lebanon set up trading colonies along the Spanish coast. Greeks also traded along the north-eastern coast. With the fall of Phoenicia, the Iberian peninsula came under the rule of Carthage, but was then occupied by Rome following the Punic Wars. The Romans ruled in Iberia for six centuries, laying such important foundations as the Latin language, Roman law, the municipality and the Christian religion.
After the Roman Empire fell, the Suevi, Vandals and Alans came to Spain but were defeated by the Visigoths who, by the end of the 6th century, had occupied most of the Peninsula.
The Arabs entered from the south at the beginning of the 8th Century. They conquered the country quickly except for a small area in the North which would become the initial springboard for the Reconquest, not to come until eight centuries later. The period of Muslim sway is divided into three periods: the Emirate (711 to 756), the Caliphate (756-1031) and the Reinos de Taifas (small independent kingdoms) (1031 to 1492).
In 1469, two Catholic Monarchs were married: Isabella of Castile and Ferdinand of Aragon, who prepared the way for the two kingdoms to be united. This union marked the opening of a period of growing success for Spain.
1492 heralded the discovery of America by the Crown of Castile under the command of Christopher Columbus. Then the Canary Islands became part of Spanish territory (1495), the Kingdom of Naples was taken from France and Navarre was incorporated into the Kingdom.
During the 16th and the 17th, witnessed the Spanish Empire become the world's foremost power, and a huge presence in European politics.
In 1808 Joseph Bonaparte was installed on the Spanish throne, following the Napoleonic invasion. A fierce resistance followed and Spanish rule was restored with Fernando VII occupying the throne.


A structure is a group of elements somehow united to support a load with stability. Examples of structures are  bridges, electricity pylons or dams. Can you think of others?.
Well, you'll probably think of tall buildings or long bridges, but there are also other examples such as chairs or tables that  we use every day. Even an egg has a structure.
In the image on the left, a modem skyscraper with two main structure
a) A skeleton, or frame, made of steel.
b)  The “skin of the skyscraper " is the walls that are made of glass panels and thin concrete sheets.

 All structures must be capable of withstanding the loads and forces for which they are designed. This does not however mean that they must always be rigid; some structures are designed to be flexible. Flexible structures are often more able to withstand dynamic forces. These are forces that change direction and quickly become more intense. Buildings, such as those built in earthquake regions of the world, can be made flexible.

Structures classifications: Shell structures and Frame structure

A shell structure is one in which the strength reloads into the outer surface.  They are usually lighter than frame structures. For example, A turtle, an egg, an airplane, a boat,  a lobster or a car has a shell structure .
In a structure the form is very important.  The resistance of the structure depends on its form.  A good example is an egg.

Test:  Get an egg and place it vertically between your index finger and your thumb.  Now squeeze hard.  You will see that however hard you squeeze, you will not be able to break the egg.  You can even do it with both hands, by interlacing your fingers and squeezing the egg between them so that force is applied at both the lower and upper ends of the egg.
Sometime we use objects that are a combination of both structures.  An example is a Chair.   There is  a tubular steel frame structure ( whose function is to support the load ) and a shell structure ( piece of wood, plastic or metal  which you sit on ).


In this video you can find sources to study the plants


In this video you can study the stages of mitosis