lunes, 16 de diciembre de 2013

4 rocosos y 4 gaseosos, ¿por qué?


Como sabéis en el sistema solar, los cuatro planetas más cercanos al sol son rocosos y los cuatro más alejados son gaseosos.

¿Coincidencia? ¿Hay alguna razón?

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lunes, 9 de diciembre de 2013

Bouncy egg. What's going on?

In one of my classes, not long ago, one of my students came up and showed me this:




Some students believed it was an egg made of rubber, some asked whether it was edible, if you could bounce it off the floor...

So i thought it could be a good activity to try and answer a few questions about that "bouncy" egg.


Check out how you make a "bouncy" egg:




The egg was introduced in a glass full of vinegar. After a while, bubbles started to come out of the glass. The egg natural color start to fade away, becoming lighter. After a few days the egg increased its volumen, changed its texture and became elastic.


Ok then, what happened to our poor little egg?


I'd like to know:

  1. What is the gas that is released in the experiment?
  2. What is the substance the egg shell is made up of?
  3. What is the chemical reaction that makes the shell "disappear"?
  4. Why does vinegar make the shell of the egg disappear and not water, for example?
  5. Why did the egg increase its volume?
  6. Why does the egg become bouncy?
  7. The websites you have looked up to come up with your answers
  8. The things you didn't understand when reading info on the web
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