CBSE Book Class 8 Science Activity The Story of Magdeberg Hemisphere

FORCE  & PRESSURE

Long Time ago there was a man called Otto von Guerick who lived in the town of Magdeberg in Germany. One day he invited everyone in the town to come and watch a spectacular event. All the people who came to watch were very impressed with what he had done. Do you want to know what happened? He took two large  copper  hemispheres  that  fitted  together.  He  pumped  out  air  from  in  between  these  two hemispheres.  He  then  tied  sixteen  horses,  eight  on  each  side  of  the  hemispheres.  But  what  was  so spectacular  about  this?  However  hard  they  were  made  to  pull,  the  horses  were  unable  to  pull  the hemisphere  apart!  But  as  soon  as  Mr.  Guerick  allowed  air  into  the  sphere  again,  the  hemispheres separated. Isn't that wonderful?

Many of you must be wishing that if only you had horses, rope and copper hemispheres to try it out again. Well! You don't need all these. You can repeat the Magdeberg experiment with very simple things too!

What to do: 

1.Take two tins of the same size. Estimate the diameter of the mouth of the tin.

2.Cut out a circle from the filter paper that has  a  diameter  slightly  larger  than  the diameter of the mouth of the tins.Draw  a  circle  of  radius  about  2cm  less than  the  radius  of  the  circle  cut  out earlier.Cut along the inner circle so as to make a hole. (fig.1)

3.Wet  this  filter  paper  circle  by  just dipping it in water. Now place it on top of one of the tins. (fig.2)

4.Burn a few strips of paper and drop them in the same tin. 

5.Quickly place the second tin on the first so  that  the  mouths  of  the  two  tins  are one  above  the  other  and  the  circular sheet  of  paper  is  in  between  the  two tins. (fig.3)

Now pick up the upper tin. What do you find? Does the lower tin also follow the upper one? Do they seem glued together.?

Please refer to the link below - CBSE Class 8 Science Activity The Story of Magdeberg Hemisphere