While the class is quiet, a garden grows. Every so often a new plant comes up: sunflowers, tulips, a pumpkin, cabbages. If the class is loud for more than a moment, the newest plant droops and goes back into the soil.
When all 12 plants are up, butterflies come and the class earns a star.
The computer's microphone listens to the room. Nothing is recorded or sent anywhere.
Stay quiet for 3 seconds.
The red line on the noise bar is how loud is too loud. Drag it, or use − and +. Measure room sets it again if the room gets louder, for example when a fan comes on.
Without a microphone, hold Space or press and hold the garden to make noise.
Keyboard: P pause, ↑ ↓ the red line, C measure room, M sound, F full screen.
The pixel drawing comes from Pixel Plays by Amir Mushich (MIT licence). The listening comes from Quiet Critters.