Things need :
· Glass jar with narrow neck
Position a funnel in the neck of the jar.
Seal it tightly with plasticine.
Fill the funnel with water.
The water cannot flow into the jar. Now make a hole in the plasticine , the water flow into the jar because the pressure is same inside and outside of the jar.
( i.e ) why you need to make a holes before you can pour liquid from a tin.