Online Experiment: Continuity equation

This online experiment of the University of colorado clearly shows how the flow velocity of a fluid changes according to the cross-sectional area of the pipe. For this purpose, the pipe can be reshaped at various positions and the volume flow can be adjusted. The velocity, flow rate and cross-sectional area can be measured virtually at any point of the pipe.


Explore pressure in the atmosphere and underwater. Reshape a pipe to see how it changes fluid flow speed. Experiment with a leaky water tower to see how the height and water level determine the water trajectory.

Sample Learning Goals

  • Investigate how pressure changes in air and water.

  • Discover how you can change pressure.

  • Predict pressure in a variety of situations.

  • Determine how fluid motion affects the pressure.

  • Figure out how to convert water pressure to water velocity.

PhET Interactive Simulations / University of Colorado Boulder /