Site Navigation

Your Account

Choose Language


Major VersionM

by Procheta Mallik


Where is the pressure of water higher: on the ground floor or the top storey of a building? Here we create a scenario with two bottles and some straw pieces replicating that scene!

    • Handle the scissors/cutter with care

    Add Comment

  1. Use 2 identical bottles, preferably small ones, about 200-300ml in volume
    • Use 2 identical bottles, preferably small ones, about 200-300ml in volume

    • Take long straw as 15cms and other 3 small straws of 3cms

    • Using scissors, make 2 holes on each of the caps so that the stiff straws fit in snugly

    • Both caps will have 2 holes on each, almost like eyes!

    Add Comment

    • Fix two of the small straws in one of the bottle caps, as shown in the picture, such that they protrude at different heights from the top

    • Fix the full straw and the other small piece on the other bottle cap.

    • Make sure that in both bottle caps, the level of the protrusion of the shorter straws is the same on the outside.

    • Fill the bottles with water (preferably coloured to make it more fun and visible!) till the brim and screw the caps on tightly


    The length of both straws should be same on the lower side of the bottle cap as well. You can’t have one longer and one shorter there.

    Procheta Mallik - Reply

    Yes, absolutely. Why hasn’t this been changed yet?? Vishal put this message 3 months ago!!

    Procheta Mallik - Reply

    • Invert the full bottles simultaneously over a receptacle, or sink, or outdoors

    • What happens next??


    1) The difference is expected to be more.

    2) The longer straw bottle should be emptied completely.

    Procheta Mallik - Reply

    • Do the bottles empty at all? At the same rate?

    • If not at the same rate, which one empties first? Why?

    • Why are two straws put in each bottle cap?

    • Try emptying the bottle using only one straw!

    Add Comment

    • The bottles are not of identical volume

    • Holes on the bottle caps should be tight enough to hold the straws; if they aren't, you can glue the gaps

    • The bottles were not inverted simultaneously

    • The straws get squeezed in the bottle cap holes, thereby preventing an outflow altogether

    • Small straws of equal length

    • Straws not aligned properly inside the bottle cap

    Add Comment

Finish Line

Suchitha Vishwa

Member since: 05/02/2017

1,910 Reputation

30 Guides authored


Content Creation Member of Content Creation


1 Member

30 Guides authored


Add Comment