Warning! JavaScript must be enabled for proper operation of the site.

Water Tank Filling

by Dan Meyer


Act One

  • Dan Meyer

    Dan Meyer

    January 08, 2012

    How long will it take?

  • 1.

    What's a guess you know is too high?

  • 2.

    What's a guess you know is too low?

Act Two

Act Three


  • VideoThe water tank emptying
  • 4.

    How long will it take the water tank to empty? What's your guess?

  • VideoFlow rate emptying
  • VideoAnswer
  • Teacher note
    This is an attempt to draw out students who apply a rates model without thinking about whether or not it's appropriate. In fact, the water fills at a constant rate but it doesn't EMPTY at a constant rate. The water empties faster the more water is IN the tank because the weight pushes it down. It's just a productive gotcha moment.

show 65 more questions


Join or sign in to leave a comment.