• Brainly User
u can make models on heart,nerve cell.digestive system  if not some other important organs in our body or else u can make some working models on electric circuit etc or else u can make  models even on plants related to photosynthesis and so on .or else u try to explain how volcanoes erupt my MAKING  MODELS U CAN EVEN MAKE MODELS OF SOLAR SYSTEM IF U WANT
you can even show how electricity reaches our homes
Plzz explain with details
Can u tell how to make an electromagnet or electricity generation by solar cell
hmmm i dont know u are in which class
M in 9th
The Brainliest Answer!
Take a wooden plank and tie 2 sytroform cups upside down to it
heat it.
one cup will move slightly upward
this shows that hot air is lighter than cold air 
take an electric motor 
fix a round disc of paper and connect cell to it
when it will spin ask the viewer to draw a straight line with pencil on disc
after they draw stop the motor and show the line
it wont be straight
tell them
hence than its the centrifugal force deflects winds on the earth
on the same disc ask them to balance an eraser
it will fall down 
hence if there was only centrifugal force governing the earth we would also have been thrown away
hence gravitational force is very essential for our existence
1 5 1
so which one did u do?
Good luck for the fair
I did no one but thnks dude