Have students write Knock-Knock jokes in Scratch by making a conversation between sprites to motivate the introduction of broadcast blocks.

  • Generally, students will use wait blocks to create Knock-Knock joke conversations; however, broadcast blocks are much more appropriate in this context.
  • Once students have created their Knock-Knock joke, ask them to arbitrarily change the timing of the conversation.
    • The students will soon realize they have to change everything in order to change the timing.
  • Introduce the broadcast block once they have changed the timing in a way that disrupts their program to demonstrate that it is necessary to use tools like broadcast blocks for dependent interactions.
    • Note from the CS Teaching Tips Team: This strategy for introducing broadcast blocks is a pain point. Check out Sean Stern’s tip about another pain point in Scratch.

More about this tip

External Source
Keledy Kenkel from the CSNYC Tip-A-Thon.