El taller se repitió en 6 ocasiones a los diferentes grupos formados procedentes de San Clemente y 1º y 2º ESO de nuestro propio centro. La duración de cada taller era de aproximadamente 30 minutos y el número de alumnos oscilaba entre 20 y 30 por turno.
El guión del taller fue el siguiente:
What are we going to do?
Turning copper coins of 5 cents into silver and gold.
What do we need?
- Heating plate
- Beaker
- Glass stick
- Wood pincers
- Spoon
- Burner
- Distilled water
- Sodium hidroxyde
- Zinc metal
- Gloves
- Googles
- Mask
How are we going to do it?
1.- We immerse coins in a boiling solution with zinc and sodium hydroxide.
2.- At this point, coins become silver.
3.- We take out the coins and wash them with distilled water.
4.- We heat the silver coins on the burner to turn them into gold.
What happened?
- The coins of 5 cents are made of copper.
- We introduce them into the dissolution of zinc and a complex of zincate is formed, giving them the silvery appearance.
- Galvanised coins are put on the fire and an alloy is formed.
- The alloy of copper and zinc is called brass and it has golden appearance.
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