Classroom Sound Monitor

Controlling physical systems with Scratch

Age: 7-11 years

Type: Scratch

Curriculum Links to: Science, D&T

The Classroom Sound Monitor has been rated 4 stars


In this activity pupils create a sound monitor for their classroom. The sound monitors they create are examples of control programs they take information from an input sensor (a microphone), and use this information to alter the output of the program (displaying a warning message if pupils are too noisy).

Optional: Schools with Lego Education WeDo hubs and motors may choose to use this equipment to have an additional movement output, such as waving a flag when pupils are too noisy.


  • I can write a control program.
  • I can create a control system.


  • Informal teacher assessment of progress during lesson. Focus on: pupils’ understanding of functions of input, output devices and of control programs; pupils’ design for a sound monitor; pupils’ ability to implement design as program in Scratch.
  • Formal summative assessment of designs and Scratch projects (completed in pairs).


This lesson in your curriculum


  • Design, write and debug programs that accomplish specific goals, including
    controlling physical systems
  • Work with various forms of inputs and outputs


  • Recognise that sounds get fainter as the distance from the sound source increases
  • Making systematic and careful observations and, where appropriate, taking accurate measurements using standard units, using a range of equipment, including thermometers and data loggers.

Design & Technology (optional)

  • Generate, develop, model and communicate their ideas through discussion, annotated sketches, cross-sectional and exploded diagrams, prototypes, pattern pieces and computer-aided design
  • Apply their understanding of computing to program, monitor and control their products