Grafeno

¿Qué es el grafeno?

-El grafeno es es una alotropía del carbono; la cual consiste en un teselado hexagonal plano (como un panal de abeja) formado por átomos de carbono y enlaces covalentes que se formarían a partir de la superposición de los híbridos sp² de los carbonos enlazados.

 ¿Cuáles son sus principales características? 

• Algunos científicos de la Universidad de Ilinois en Míchigan aseguran que el grafeno tiene propiedades de autoenfriamiento.

• Alta conductividad térmica y eléctrica.⁴

• Alta elasticidad y dureza.

• Resistencia (200 veces mayor que la del acero).⁵

• El grafeno puede reaccionar químicamente con otras sustancias para formar compuestos con diferentes propiedades, lo que dota a este material de gran potencial de desarrollo.

• Soporta la radiación ionizante.

• Es muy ligero, como la fibra de carbono, pero más flexible.

• Menor efecto Joule; se calienta menos al conducir los electrones.

• Consume menos electricidad para una misma tarea que el silicio.

• Genera electricidad al ser alcanzado por la luz.⁶

¿Qué aplicaciones se te ocurren?

-Múltiples aplicaciones, la mayoría de ellas en el campo de la electrónica (recubrimiento de pantallas táctiles, almacenamiento de energía y datos, pantallas táctiles flexibles y enrollables..), hasta la "simpleza" de ser usado como material aislante, por ejemplo. 

Fuente: Wikipedia. Grafeno 

Marco Polo's Magic Stones

Here you can see some questions about the text "Marco Polo's Magic Stones". Enjoy:

• Who was Marco Polo?

Marco Polo was a Venetian merchant traveler from the Venetian Republic, whose travels are recorded in “Il Milione”, a book which did much to introduce Europeans to Central Asia and China.

• What historical period is the text from? What do you know about this period?

Text is from the year 1298 (13^th century).

This period were an age of many changes, discovering new things, until this moment unknow, such as the gunpowder.

• Compare the technological development of the East with that of the West during this period.

We can know throught the Marco Polo´s text  that in  Catay people used mineral coal  to heat and cooking, which was cheaper and lasted longer than the charcoal that we used in Europe in that period. He says they use it in public bathrooms and kitchens also, even the rich people had them in their homes.

In that period the Far East were more avanced than the West in other fields. They invented the compass, gunpowder, paper and they had a high technologie in glass. This it was very important to make lenses and telescope. 

• What regions does the text discuss? What do we call it nowadays?

The text speaks about Catai a province located in the mountains.

• What stones do you think the text is talking about?

I think that it’s talking about the coal, because it talks about black stones that are very flammable and you can found it in the mountain.

• Why do you think the book was given this title?

Because these stones can make flames, so making fire, such as a magics stones.

• Was there an equivalent to these stones in the West?

Yes, the equivalent in the West was the charcoal. The charcoal is getting from the wood.

• What properties and advantages do the stones in the text have?

These stones could make fire, but with little flames.

The magics stones could stay alight for the whole night, and gives out a lot of heat. 

Isabel Pavón and Horacio García made this work.