Science experiments for children – Bed of nails . When the pressure is distributed on many nails, each nail exerts a lower pressure, insufficient to burst the balloon: all the pressure exerted is distributed equally between the nails and the pressure points are spread over the entire surface of the balloon. When we use a lower amount of nails, each nail exerts more pressure and the balloon bursts: all the pressure is concentrated on a few points.
In this example is used a bed formed by nails 25 and a weight by half a kilo. It then compares with a bed formed by a single nail and the same weight:
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Science experiments for children – Bed of nails
Build with the children the bed of nails
You will need a piece of wood for the bottom, where you can attach two rods upright on either side, to enter the upper tablet (provided with two holes corresponding to the rods of the tablet bottom).
On a smaller tablet planted a hundred of nails, in such a way that they protrude from the opposite side to form your bed. If you want you can also use a table of polystyrene for simplify the operation.
If you want make the comparison predispose other tablets of the same size, but with a lower number of nails, and one with a single nail.
Prepared also some weights (which may also be packets of sugar or flour or stones previously weighed and marked).
Proceed with the experiment.
If you follow the gradually from a nail in a growing number of nails, the experiment will be much more interesting for the children, who will see the first burst a number of balloons, and then … surprise!
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Science experiments for children – Bed of nails
http://www.education.com/science-fair/article/relaxing-bed-nails/ http://www.naturesraincoats.com/Royal%20Society%20Exhibition_Bed-of-Nails.html https://www.tes.com/teaching-resource/bed-of-nails-cool-science-experiment-6255199
