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by Dan Meyer


Act One

  • Dan Meyer

    Dan Meyer

    July 31, 2015

    How long will it take the lava to reach Tarata?

  • 1.

    What is an answer you know is too high & too low?

Act Two

  • 2.

    What information would be helpful to know?

  • Teacher note
    Students may ask about terrain. Tell them for our purposes the terrain is completely flat between the volcano's base and Tarata. When the subject of rates and distances comes up, pass out a ruler and the following handout.
  • FileHandout
  • Teacher note
    Have the students calculate how long it will take the lava to reach Pembroke before attempting Tarata. Many will divide the DISTANCE traveled in an hour by the distance to Pembroke. This is the central, and interesting misunderstanding.

    The lava doesn't travel a constant DISTANCE in an hour. It travels a constant area.

    So play the Pembroke video, which will confirm some students' work and disconfirm others. Then ask them to speculate why they might have gotten the wrong answer.

    Then help them understand how to calculate the area of the ring.
  • VideoThe Pembroke Moment

Act Three

  • Teacher note
    Before they calculate Tarata, make sure the students who got Pembroke wrong initially can go back and calculate it correctly.
  • VideoThe Answer
  • FileSample Student Work


  • 3.

    What could the y-axis be labeled for each of these graphs about the volcano & lava? Also, draw your own sketch about the volcano & lava.

  • ImageGraphs

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