1.09: Tidy Up the Code with Repeat Blocks

Warm Up

Share the objectives and success criteria from the presentation.

Play the word game that requires learners to repeat everything that everyone says before them:

• my name is John and I like jaguars,
• my name is Lisa and I like lemons and this is John and he likes jaguars
• my name is Ashley and I like apples, this is Lisa and she likes lemons and this is John and he likes jaguars.

Depending on class size, it might be wise to have this done in smaller groups so that less time is taken. The idea of the game is to get used to things repeating.

Read the story text from the presentation. When you reach the section on planning and comparing the blocks between MartyBlocks Jr and MartyBlocks, have learners engage with the group tasks in their workbooks.

Get Learning

Have learners look at and discuss two of the repeat blocks in the Control section:

• what they do differently;
  • one has an argument that allows you to set the number of times the code will repeat and the other will only end when the stop icon is pressed (there are other ways to stop the forvever repeat block but it is suggested that you do not mention more, yet, as they are more complex).
• what they do that is the same;
  • they both repeat the code, within the block
• when you would want to use one instead of the other;
  • when you want the repeat to occur a specific number of times vs when the number of times is not important
• when you would have to use one over the other, when one has a limitation that wold cause problems in a program.
  • when repeating too often would cause Marty to walk over an edge or into an obstacle

The presentation shows two examples of code the village children have created in MartyBlocks. After time for learners to discuss how they think they would improve the code, a mouse click will reveal an example for a more efficient version, which makes use of the repeat block. Do not limit the discussion to this as the only correct answer. Encourage learners to compare any contrasting thoughts they may have had with what is presented on the slide.

Cool Down

Bring learners back together to discuss the challenges they faced and overcame. Have groups model their creations and explain what is happening, when. Encourage other groups to compare their work and ask questions to deepen their understanding of the processes.

Suggested questions you might ask:

• Do you prefer the repeat block in MartyBlocks or MartyBlocks Jr (if applicable)
• Do you prefer reading code that has the repeat block or does not have it?
• What challenges did you face when converting from repeat-free plans to plans and code with repeats.

Carry out any end of lesson routines.

Log off devices and clear everything away.