Broken

1. Prepare

• Read through the student material in the LEGO^® Education SPIKE^™ App.

2. Engage (5 Min.)

• Use the ideas in the Ignite a Discussion section below to engage your students in a discussion related to this lesson.
• Use the video to explain the lesson.

3. Explore (35 Min.)

• Have your students work in pairs to build the CNC machine, have them keep in mind that they're building a non-functioning machine.
• Ask them to run the program and to try to identify and correct the issues they see.
• Remind them to document the problems and their solutions.

4. Explain (10 Min.)

• Facilitate a sharing session. Encourage your students to talk about the problems they found and the solutions they came up with.

5. Elaborate (25 Min.)

• Ask each team to improve their CNC machine by modifying their build and/or program.
• Have them take turns sharing their improvements with the class.
• Don't forget to leave some time for cleanup.

6. Evaluate

• Give feedback on each student's performance.
• You can use the assessment rubrics provided to simplify the process.

Start a discussion about iteration or fixing things by asking relevant questions, like:

• What's usually your first reaction when something breaks?
• If you're going to fix something, what will you do first?
• What's the last thing you've fixed? How did you find the problem?
• What's a CNC machine? Do you know what it's used for?

Have your students watch this video to see what they're about to do.

Tandem Build
Split each team's building tasks to ensure that everybody is actively involved:

• Student A: top of the CNC machine
• Student B: bottom and needle of the CNC machine

Pre-designed shapes
You can use blank sheets of letter-size paper for this lesson but pre-designed PDFs of CNC cuts are provided. By using these pre-designed sheets, it'll be easier for your students to figure out whether or not the CNC works.

Loading the Paper
Here's how you load the paper:

Looking for Issues
The CNC machine model has 4 real issues that must be fixed in order for the program to work as intended:

1. A paper feeder wheel is missing, causing the Y axis to not work properly.
2. The top of the CNC machine isn't correctly attached to the bottom.
3. The paper feeder gears are inverted, causing the paper to enter the CNC too quickly.
4. The pencil carriage isn't affixed, causing the X axis to work improperly.

Easy Fixes
Here's the easiest way to fix these issues, though keep in mind that the objective of this lesson is for your students to find their own solutions.

Possible Upgrade
Your students can upgrade their CNC machines by adding a Color Sensor.

Have your students write pseudocode or verbally describe what each line of the program does before activating it.

Main Program

Possible Solution

Remember to press the Left Button on the Hub to activate the programming stack.

Remember to press the Right Button on the Hub to activate the programming stack.

Simplify this lesson by:

• Suggesting a selection of bricks your students can use to fix the issues
• Asking all of the teams to work on the same upgrade so it's easier to assess the improvements

Take this lesson to the next level by:

• Having your students draw complex shapes on the printer, including curves
• Having your students transform this model into a 3D printer by adding a Z axis

Teacher Observation Checklist
Create a scale that matches your needs, for example:

1. Partially accomplished
2. Fully accomplished
3. Overachieved

Use the following success criteria to evaluate your students' progress:

• Students can describe the function of an object.
• Students can describe the benefit of an object's features against needs.
• Students can construct effective arguments.

Self-Assessment

Have each student choose the brick that they feel best represents their performance.

• Blue: I can describe how things work
• Yellow: I can describe in detail how things work and I can highlight what it's good at.
• Violet: I can convince someone that I've invented the coolest thing in the world.

Peer-Assessment
Encourage your pupils to provide feedback to one another by:

• Having one pupil use the coloured brick scale above to score another pupil’s performance
• Asking them to present constructive feedback to one another so that they can improve their group’s performance during the next lesson

To incorporate language arts skills development:

• Have your students work hands-off to role-play calling a customer support line.

  ▷ One student describes the problem.
  ▷ The other student explains how to fix it.

Note: This will make for a longer lesson.

To incorporate math skills development:

• Have your students find the gear ratio of the paper feed.
• Ask them to use appropriate language to describe how it controls the speed of the paper entering the CNC.
• Have them explain (and try!) what would happen if the gears were swapped.

Note: This will make for a longer lesson.

Students who enjoyed this lesson might be interested in exploring these careers pathways:

• Business And Finance (Entrepreneurship)
• Education And Training (Teaching)
• Media And Communication Arts (Broadcast Technology)