Resource 15

Engineering dunnies ¹

The task

A cartoon of someone sitting on a toilet

You are an engineer with the job of designing a new toilet system for the firm of Dinkum Dunnies. You have to try to develop the maximum flush, with a minimum volume of water.

You will need:

One rule of this activity is no mess. All of the water should end up in the sink.

  1. On your own, plan what you would try to do. Share your ideas with your partners and agree on a common plan. You might try different widths of tubing, different funnels or changes in the height of the apparatus.
  2. How could you measure the strength of a flush? You could measure the length of the water jet. That might give some idea of force.
  3. Write down the draft plan and discuss it with your teacher.
  4. Do the experiment.
  5. Write up your experiment as a letter to the firm of Dinkum Dunnies.

¹ Based on an activity from: Keith McTaggart and Paul Saddler 1993, Flushing Dunnies, Melbourne Water and Science Teachers Association of Victoria.