water pressure (Urdu and English)
Punch 3 or 4 small holes, one above the Other, along the side of an empty milk carton or a large can. Cover the holes with a long strip of adhesive tape and fill the carton with water. Then place the can in the sink or a basin and pull off the tape. You will see that: The stream from the lowest hole travels farthest.
Explanation: The water at the bottom of the carton has the force exerted by the pressure of the water above it. Like air, water has pressure. Water pressure depends, as your experiment shows, on the water’s depth. Many cities pump water into raised tanks. This is done to give the water enough force to run up into people’s homes from pipes beneath the ground.