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Marty Image

0.06 Estimating the Steps

45 Minutes

Lesson Overview

In this lesson, learners will begin to use estimation for their routes for Marty: about how many steps will it take to get to an object or a person?

This will be the beginning of a proper plan that will require testing and retrials.

Key vocabulary:
    Direction, Forward, Back, Left, Right, Instruction, Estimation,

Content Sections

  • Learning Objectives
  • Warm up
  • Get Learning
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  • Time for Practice
    1. Cool Down
    2. Extensions & Challenges
    3. Extend
    4. Support
    5. Additional Reading
    6. 0.06 Estimating the Steps

      45 Minutes

      Lesson Overview

      In this lesson, learners will begin to use estimation for their routes for Marty: about how many steps will it take to get to an object or a person?

      This will be the beginning of a proper plan that will require testing and retrials.

      Key vocabulary:
        Direction, Forward, Back, Left, Right, Instruction, Estimation,
      • Experience with the Marty Controller (lesson link is in additional reading), awareness of estimation
      • Tablet with Bluetooth 4.2+
      • Marty the Robot V2, Marty Workbook, Marty Controller, in the Marty the Robot App

      Learning Objectives

      I can estimate how many steps it will take for Marty to reach a goal.

      For this entire lesson, Marty should be on the ground, not on a table.

      Warm up

      Share the learning objectives and success criteria from the lesson. Say to learners, "We are going to practice thinking about how far away something is. We might not get our answers perfect, which is perfectly OK; let's focus on getting better."

      Have learners sit in a circle for the game that is described in the resources section. The purpose of the game is to have learners focus on listening: about where is the sound coming from? Which will lead in to estimating distances.

      Get Learning

      Read the story from the presentation to introduce the focus of the lesson. The story text is longer than usual but is needed to highlight the misconception that estimates should be exact values, correct on the first attempt, when estimates should only be about using what you know to determine what you don't.

      Have your Marty on the ground, on a marked x - masking tape is a good idea. Have at least three objects around Marty at different distances and angles from them. A good idea would be to label them objects 1, 2, 3, or some other naming convention. The image below gives one suggestion.

      Have learners stand up and look at how far away Marty is from the 1st object. Suggest learners close their eyes and count as they picture Marty walking that distance. Have learners record their estimate in their workbook if there is an opportunity to do so. As a class, ask learners for their estimates and record them on the board. Perhaps a name or initial beside a number the first time a value is suggested and a tally mark for each additional time that number is suggested. Have groups record a selection of estimates from the board in their workbooks, it should look something like this:

      Point Marty in the direction of the object and press the forward arrow the number of times required for the first estimate - a good idea is to start with the value that is the least to give learners an idea as to how far that estimate takes Marty and compare from there. Just before starting to tap the forward arrow, remove the object and replace with tape or some other marker, in case the estimate is too much.

      For the second estimate, choose the one that is the greatest value. It is best to hide Marty's movement as the arrow is pressed so that they cannot determine the exact number of steps, should Marty cross over the mark because the estimate was too great. If the estimate was very accurate - Marty touched the objects or was a hair's breadth from it - congratulate the estimation with words of praise to support the estimate, something like, "That was a very accurate estimate," or, "that was extremely close for an estimate, good thinking." In this instance, extend congratulations to similar estimates complimenting how close the values were.

      For estimates that ended up with Marty quite far away from the object, you can choose to either tell learners, "These estimates weren't quite right, it seems that Marty's steps are a bit bigger/smaller than you thought," or you could ask, "that estimate is close, does Marty need more or fewer steps?" This would allow for discussion as to which estimate you could try next. Once learners determine if Marty walked too far or not far enough, look at the list of other estimates and have the class select the next value that is either greater or less than the previous one, depending on what you need. Bring Marty back to the x and check the next appropriate value in the list. Repeat this as little or often as you want. Have learners record the description of the estimate (not far enough, too far, or other descriptive phrases) and the actual distance to the object, in their workbooks.

      For the other estimates, you might record something like this:

      Repeat the whole process with the second and third objects.

      This video shows the shortest estimate followed by the longest estimate. The longer journey has the middle edited out so that learners cannot count the exact number of steps as Marty takes them. You could use this video as a way to have learners use the higher and lower end of the estimates to improve on what was initially thought.

      Here are other individual step videos with 'estimates' for Marty, they are all featured in the presentation in a slightly more interactive way.

      17 steps

      24 steps

      28 steps

      Time for Practice

      For learner-led estimations, there are two options for setting up the activity:

      • Before the lesson starts, have multiple objects arranged around the room and multiple xs around the room. Each x will have objects close enough so that learners can choose three for estimation purposes. Carry out the process that was modeled as a whole class; each distance estimate should take less time because groups will have fewer members. Each object should have estimates recorded in the workbook but do not do three estimates at once: do them one at a time, following the process from the whole class procedure.
      • Before the lesson starts, provide each group with tape to mark an x for their starting point. Provide learners with a selection of objects that they will need to place around the room sp that they can estimate distances. Encourage learners not to put Marty too far away, making the estimation very difficult, or too close. Each object should have estimates recorded in the workbook but do not do three estimates at once: do them one at a time, following the process from the whole class procedure.

      Cool Down

      Remind learners of their fantastic estimation skills and share with them that this skill will be so needed for future work. Share with them what they accomplished, "You were able to estimate a distance and then you improved on your estimates! Fantastic work!"

      Ask learners if they think they did well with the lesson using a familiar formative assessment strategy: thumbs up for good, thumbs to the side for OK, thumbs down for not so good; a green, yellow or red card, indicating their thoughts; a one to one chat about the learning; whole class feedback using a PMI (plus, minus, interesting) approach; or some other strategy with which the learners are familiar.

      Read the closing part of the story, to close off this lesson and tie it into the next part.

      Carry out any end of lesson routines.

      Log off devices and clear everything away.

      Extensions & Support

      Extend

      Challenge learners to find the difference between their estimates and the actual distance. Set challenges that are farther away, but require learners to estimate how many steps they need to take to reach the goal.

      Support

      After checking each estimate, make a mark on the floor with the number of steps. This can be used to compare group member estimates for each object and to inform future estimates for the other objects.

      Additional Reading

      User Guide for the Marty Controller

      Reminders of the learning from Introducing


      • Technologies: Computing Science
      • Literacy & English: Listening and Talking
      • Health and Wellbeing: Mental, Emotional, Social and Physical Wellbeing
      • Numeracy: Number, Money and Measure
      • Literacy & English: Writing
      • CSTA Education Standards
      • Digital Technologies, Design & technologies: Digital Technologies
      • Computing, Design and Technology: Computing
      • International Society for Technology in Education (ISTE)