Monday, August 31, 2009

Make a rainbow over your hands



This book uses the same principle of a flip book to give us the visual sensation of a rainbow.
The way in which a real rainbow is formed is very different. In the sky the colors are formed by the decomposition of white light inside of little particles of water that make the clouds.
Here a strep with some colors of rainbow is placed in each page of the book, when we flip it the rainbow appears. A phenomena called visual persistence allows that, to see more about visual persistence click here.
Tuesday, August 11, 2009

Leidenfrost Effect: putting the finger inside molten lead


This video show the physical principle that allows put the finger inside a molten lead without burn it.
The humidity of ours skin evaporates and the molten lead do not touch the finger.
The same happens with water drops in contact with a very hot frying pan . They don’t evaporate immediately because a vapor layer protects the drop from the heat.
Saturday, August 8, 2009

Learn how to do a sodium dichromate volcano

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Sodium dichromate is a orange solid. During its decomposition N2 , water and chrome oxide are liberated. The total volume increase in about 30 times. Some chrome oxide dust and the heat liberated make it really seamed with a true volcano.

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