INERTIA

Samaresh  Goswamy 

My idea  of  writing  these simple  science  experiments  is  to  develop  a  spirit  of  inquiry  in  the  minds  of  school students  so that  they  get  an interest in learning  science. This  reminds  me  of  a  famous  Chinese  proverb " I  see  I forget  I read I remember,  I  do I  understand " essentially  it means  science  can  be  best  learnt by " doing in your  own  hands ".

Let us now  learn what  is  Inertia. This  will  be clear by doing  this  experiment at home  by yourself  or with  the  help  of  your  parents. 

   WHAT  ARE  NEEDED:

*  A boiled egg

*  A raw egg

*  A table

WHAT  TO  DO:

*  Place  The  eggs on the  table  or on the  floor 

*  Rotate  the  eggs one by one by spinning  them with  your  fingers 

*  When they  Rotate,  try  to stop  them by gentle tapping  with  your  fingers 

WHAT  TO  OBSERVE  :

*  As you  tap the  boiled egg it stop  immediately 

*  But  when  you  tap the  raw egg , it stops for  a short  while and  then  start  rotating  again  as you  lift your  fingers 

WHAT  IS  GOING  ON  :

  Matter  inside the  boiled  egg solidifies when  it is  boiled.  This  boiled  egg behaves like  a  single  solid body, because  of  the  solid  Matter inside. So when you  tap the  boiled  egg  immediately  it comes  to  rest. Now  a raw egg  has two  parts  an outer shell and a viscus liquid.  When  you  stop the  rotating  raw egg momentarily , it's outer shell comes  to  rest but the  inner  viscus liquid  continues  in motion due to  its  inertia  of motion. Being  in motion its inner  liquid  gets  some kinetic  energy. As the  moving liquid  in contact  with  the  outer shell,  it transfers  its kinetic  energy to  the  outer  shell  and  the  shell  starts rotating again  after  a short while.