martes, 17 de diciembre de 2013

Ernest Rutherford said...






All science is either physics or stamp collecting.

Anyone who expects a source of power from the breaking down of the atom is talking moonshine.



miércoles, 13 de noviembre de 2013

¿Cuanto tardaríamos en contar 1 mol?

En muchas ocasiones la Física, la Química u otras ciencias nos obligan a manejar números muy altos o muy bajos. Las potencias de 10 y la notación científica nos permiten expresar de forma sencilla estas cantidades pero a veces no nos hacemos una idea de la verdadera magnitud de dichas cantidades. La Química, por ejemplo, nos presenta el número de Avogadro (número de partículas de un mol): 6,023·1023 o, dicho de otro modo, 602.200.000.000.000.000.000.000, es decir, algo mas de seiscientos mil trillones ¡UNA AUTÉNTICA BARBARIDAD!

Imaginad que tuviésemos que contar de una en una las moléculas que hay en un mol de agua. ¿cuanto tardaríamos?
Supongamos que una persona pudiese contar 10 moléculas en 1 segundo (un auténtico virtuoso del asunto). Esta persona contaría 600 moléculas en 1 minuto, 36.000 en una hora, 864.000 en 1 día y en una año llegaría a las 315.576.000. Contando algo mas de 315 millones al año para llegar a las 600 mil trillones necesitaríamos aproximadamente 1,91·1015 años, es decir, algo así como 1910 billones de años. ¿Eso es mucho? Comparemos: el ser humano actual existe desde hace poco mas de 1 millón de años, la vida en nuestro planeta unos 3000 millones de años, nuestro planeta se formó hace unos 4500 millones de años y el Universo mismo existe desde hace “sólo” unos 14000 millones de años. Comparando esta última cantidad con el tiempo que tardaríamos en contar un mol nos damos cuenta que es mas de 100000 veces mayor que el tiempo de vida del Universo.

Vayamos un poco mas allá: supongamos que toda la humanidad se dedicase a esta absurda tarea a esta misma velocidad. Recientemente se ha anunciado que ya somos 7 mil millones de personas, es decir 7 · 109. Una simple división del tiempo obtenido anteriormente 1,91·1015 años entre los 7 · 109 habitantes de nuestro planeta, nos sale: unos 270.000 años.., como aquel que dice... un par de días

Como ves el conocido como número de Avogadro es muy grande aunque en realidad un mol no supone realmente una masa excesiva, en el caso del agua son solo 18 gramos, cada vez que te bebes un vaso estás metiendo en tu cuerpo mas de 10 moles de agua.... En la foto tienes un mol de agua.


jueves, 10 de octubre de 2013

Science News: The kilogram got weight


The International Prototype Kilogram (IPK) is kept at the International Bureau of Weights and Measures in Paris, and the metallic cylinder has been used to define the kilogram since 1889. Previously the unit had been defined as the mass of a litre of water.
Forty replicas of the IPK were made and distributed throughout the world, and now each varies in mass by a few micrograms. The increase is thought to be due to having accumulated impurities on the surface, and may be reversible by “washing” the block with ozone and UV light.
Since the kilogram is defined as being the mass of the IPK, then if that block gets heavier the kilogram simply becomes a larger mass unit than it previously was. But the problem with this is that the kilogram is one of the seven “base units” of the SI system, from which other units are derived.
For example the unit of force, the Newton, is defined as that required to accelerate a mass of one kilogram at a rate of one metre per second squared. In turn the unit of work or energy, the Joule, is a force of one Newton exerted over a distance of one metre.
The kilogram getting heavier therefore creates a domino effect in which many other units of measurement also change – and the instruments used to measure them have to be recalibrated.
The kilogram is unique in that it’s the only one of the base units currently defined via a physical thing rather than from a natural phenomenon – it’s the joker in the deck used to build this particular house of cards.
For example the metre, once defined as a proportion of the distance from the north pole to the equator, is now the distance travelled by light in one 299,792,458th of a second. And the second, once considered to a division of a 24-hour day, is “the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom”.
It’s a goal of the science of metrology to similarly define the kilogram in terms of natural physical constants. One proposal is to define it by fixing the value of Planck’s constant, which can be expressed in units that include the kilogram.
Others include defining it as a certain number of atoms of Carbon-12, or to employ a Watt balance – a type of scale that uses electrical current and voltage to measure the weight of a test mass very precisely.
Until then we can console ourselves with the fact that, despite what the post-Christmas thickening around the middle might suggest, if the kilogram is getting heavier then – at least relatively – we are actually getting lighter.


A video about the the history of the kilogram and how physicist are trying to solve this problem.

Simulador cubeta de ondas

En esta dirección: http://www.falstad.com/ripple/
podéis encontrar la simulación de cubeta de ondas con la que hemos estado trabajando en clase, por si queréis verla de nuevo.

 

miércoles, 9 de octubre de 2013

La materia


La materia 2º ESO from jvprofe

Dado que, por error informático, he perdido el resumen que habíamos elaborado en clase. Me he permitido tomar prestado este documento prestado del wiki de ciencias naturales del IES Gonzalo Torrente Ballester de San Sebastián de los Reyes. Les agradezco sinceramente la aportación 

jueves, 19 de septiembre de 2013

Variables in a scientific experiment

Steps of the scientific method

Scientific Method Song

Estados de agregación




Science and its method

viernes, 24 de mayo de 2013

jueves, 23 de mayo de 2013

Simulador de cálculo de nota de acceso a la Universidad

http://uex21.unex.es:8080/simnota/simulador.jsp;jsessionid=6A194674793DD37BF91FB08CD7E8A5DB

El título lo dice todo. Introduces la media de bachillerato, las materias de las que te vas a examinar, las notas de los exámenes (reales o posibles), el grado al que quieres acceder y el programa calcula la media aplicando las ponderaciones vigentes. Puedes ver, por ejemplo, si una de las materias que has cursado te interesa mas examinarte en la fase general o específica. 

miércoles, 15 de mayo de 2013

Elment cards: Tin by Javier Rodríguez

Element cards: Neon by Javier Rodríguez

Element cards: Plutonium by Javier Rodríguez

Element cards: Gadolinium by Manuel de Alvarado

Element cards: Osmium by Manuel de Alvarado

Element cards: Seaborgium by Manuel de Alvarado

martes, 14 de mayo de 2013

Problemas de física de selectividad

Tomado de la página de J. M. Campillo. Problemas de casi todos los temas del curso.

http://www.jpcampillo.com/uploads/pau/fisica-problemas.pdf

Element cards: Chromium by Javier Rodríguez

Element cards: Ununoctium by Javier Rodríguez

Element cards: Copper by Laura Hernández

Element cards: Dysprosium by Laura Hernández

Element cards: Magnesium by Laura Hernández

Element cards: Titanium by Laura Hernández

lunes, 13 de mayo de 2013

Element cards: Bromine by Manuel de Alvarado

Element cards: Berillyum by Manuel de Alvarado

Element cards: Sulfur by Belén Armario

Element cards: Cerium by Belén Armario

Element cards: Fermium by Belén Armario

Element cards: Francium by Belén Armario

Element cards: Mercury by Belén Armario

martes, 7 de mayo de 2013

Dualidad onda - curpúsculo

Element cards: Lutetium by Shaila Medjane

Element cards: Flevorium by Shaila Medjane

Element cards: Antimony by Shalia Medjane

Element cards: Aluminium by Shaila Medjane

lunes, 6 de mayo de 2013

Element cards: Terbium by José Ángel Guillén

Element cards: Rhodium by José Ángel Guillén

Element cards: Bohrium by José Ángel Guillén.

Element cards: Barium by José Ángel Guillén

Element cards: Radon by Carlos Ruiz

Element cards: Niobium by Carlos Ruiz

Element cards: Holmium by Carlos Ruiz

Element cards: Curium by Carlos Ruiz

Element cards: Zirconium by Lin Huang

Element cards: Erbium by Lin Huang

Element cards: Darmstadtium by Lin Huang

Element cards: Calcium by Lin Huang

Crossword: elements around us.

Elements

sábado, 4 de mayo de 2013

Element cards: Nitrogen by Carlos Sánchez

Element cards: Xenon by Carlos Sánchez

Element cards: Rhenium by Carlos Sánchez

Element cards: Tantalum by Carlos Sánchez

Efecto fotoeléctrico.


Simulación sobre el efecto fotoeléctrico





Simulación del efecto fotoeléctrico en madridmasd.org

martes, 23 de abril de 2013

Element cards: Californium by Lydia Sánchez

Element cards: Phosphorus by Lydia Sánchez

Element cards: Hassium by Lydia Sánchez

Element cards: Krypton by Lydia Sánchez

Ley de Desintegración Radiactiva.

 
N = N0 e-λt

Simulación en Java sobre la ley de Desintegración radiactiva elaborada por Ángel Franco García

lunes, 8 de abril de 2013

Periodic table cards.

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In this activity I want you to make a collection of cards about every element in the periodic table. They are 118 elements and you are twenty four, that means that each of you have to make cards about 4 or 5 elements. When we have all the cards we will have the opportunity to build a giant periodic table if we find a good place in the high school for it.


In the link below you have a list with your names and the elements you have to work about.


In order to give all of the cards the same appearance you have four examples in the link below. All of them have information:
  • Atomic number (Z): as you could know elements are ordered according to their atomic number.
  • Symbol. They are written in a special kind of characters called “Font-work” (some similar to “Word-art” in MS Office)
  • Name in both languages, Spanish and English.
  • Atomic mass, in other words, the average mass of the atoms of the element.
  • Electron arrangement: the number of electron in each shell and sub-shell in an atom of the element.
  • Physical properties: elements have lots of properties, but I have only chosen three of them: melting point, boiling point and density.
  • Discovery: Who discovered the element? When was it discovered?
  • Photograph: Be carefull with this, not any picture is valid. Get sure that you are using a photo of the element. A photo of a compound or a mixture that contains the element is not valid. The best option is a photo of an usual object made entirely of the element but this in not always easy. Some elements, mainly the ones with highest atomic number are impossible to get a photo of them because they are not stable.
  • A little piece of information about the element. Four of five lines explaining why the element is important, useful or interesting, a property of its that called your attention,...
A few tips to make easier your work (and also, not to spend too much time at class explaining all this)
  1. All of you must work with the same software oppenoffice, you can download it here:
  2. I suggest you download any sample file made by me, make a copy of it in your computer and make the necessary changes in it.
  3. Don't change the fonts, this is the only way to get an homogeneous aspect in all cards.
  4. Periodic tables usually show different properties of elements with colours. We will change the colour for the symbol (according to kind of elements) and the colour of border (according to the physical state). See the file lista.odt.

The cards must be in my email (jvprofe@hotmail.com) by 30th of April of 2013. You can email me them before if you want, but there are no reason to do it later, you have plenty of time.

Links:

A sample of what I want you to make

List of the elements that every one of you has to work

Download oppenoffice

Periodic table

jueves, 4 de abril de 2013

Algunas experiencias sencillas sobre convección.


Conducción, radiación y convección

Alkali metals and water

This video is from the Britsh TV show Brainiac. It shows us how all alkali metals react with water giving out energy.

As we can se, the heavier is the alkali metal, the more explosive is the reaction we get. 


Meet the elements.

How many elements are mentioned in this song?
Which of them are used as a simple element?
Which of them are mentioned as a component of a compound?

viernes, 22 de marzo de 2013

One of the best periodic tables on the internet

 

In this website you can get a lot of information about the properties of every element of the periodic table. You can also see the name of the elements in any language you need: Spanish, English, French, Chinese or any other one. 





lunes, 4 de marzo de 2013

Snow chemistry

This is the video we've seen in class today. On it, the professor of University of Nottingham M. Palianov explains how salt can be usefull to avoid the formation of ice on the roads and also other interesting things about snow and ice. If you didn't understand everything he says you can watch the video again.